Wednesday, February 19, 2014

Sauerkraut: skirmishes and surprises.

Having heard of the health benefits of sauerkraut, and fermented vegetables generally, I thought I would try it myself. The basic science is usefully outlined in these links In essence, bacteria naturally present on the cabbage are encouraged to grow in a saline, anaerobic environment, which convert sugars to principally lactic acid (50%), acetic acid plus ethanol (25%), along with 25% CO2. Esters may also result, so contributing to the particular and unique flavours of different kinds of sauerkraut. It is widely held that the probiotics (beneficial microbes) present in sauerkraut are helpful to the digestive system along with other positive effects on health http://en.wikipedia.or/wiki/Sauerkraut#Health_benefits. Sauerkraut that is bought in shops has been pasteurised, and so all microbes, both good and bad, have been killed.  This enables it to keep for longer and also prevents the jars from exploding under the pressure of fermentation gases. Therefore, to explore the true probiotic advantages of sauerkraut, it is essential to make it yourself, as a living food.

It is sometimes said that the word sauerkraut means "acid cabbage", but this is wrong. The German word for acid is säure (prounounced "zow-ra"), while "sauer" (pronounced zow-er) means "sour" in English. The German word for cabbage is "Kohl", and it used to amuse some of my German friends that their then leader, Helmut Kohl, was actually "Chancellor Cabbage"! Kraut means "herb", or designates the leaves and stem of a plant as opposed to the root. Hence sauerkraut means "sour herb". The term "kraut" is more often used in compound nouns for herbs, and also for cabbage and cabbage products. [Krauterbutter is butter, flavoured with a mixture of herbs such as parsley, borage etc.] The generic term "kraut" in sauerkraut emphasises that many different kinds of vegetable can be fermented, not only cabbage.

So, now to my own adventures with sauerkraut: 

There are various posts below about my sauerkraut "adventures" over the past 2 years, but here is the latest one, which is a bit more "experimental" than most of the previous batches.

(36) This time, I decided to make a "mixed" sauerkraut. Having worked mainly with fairly coarsely chopped cabbages over the past 2 years, since I began making sauerkraut, this time I chopped them very finely, since I wanted to get a good admixture of the different ingredients. I took a small red cabbage (1 1.2 lbs) and a similarly sized white cabbage, cut them both into quarters and removed the cores. I then shredded them as finely as I could with a sharp, serrated knife and blended them together, along with a grated carrot, and blended them together in a broad metal dish (about 30 cm in diameter) along with 4 crushed cloves of garlic and about a level teaspoonful of caraway seed. I added one tablespoonful of salt (15 mls) to this, mixing it all in well, and then left it for about half an hour. This allowed the salt to begin breaking down the cell walls and the cabbages mixture became soft, while liquid pooled in the bottom of the dish.

I then worked the mixture very firmly with my hands in the usual way, and after about 10 minutes the whole was very soft, and a lot of liquid had been expelled into the dish. I then packed this all very firmly into the 2 quart ( 1.3 litre) fermentation jar. Due to the fine shredding of the cabbage a much larger volume than previously could be fitted into the jar, and only a small amount (100 mls) of additional brine ( 1 tbspn of table salt in 500 mls of water) was necessary to completely cover the cabbage. I placed one of the original outer cabbage leaves over the shredded cabbage and placed an inverted jar over this to hold it down. I then filled the jar to the top with brine to keep the air (oxygen) out. I place the open end of a plastic food bag over the top of the jar, and a couple of pieces of muslin cloth on top of this, holding it all in place with a rubber band around the lip of the jar. I stood the jar in a dish, on top of a couple of pieces of kitchen towel, and let it ferment.

After a day or so, purple liquid overflowed the jar in collected in the dish, which I drained off and poured down the sink. As the fermentation slackened over the next few days, I added water to the jar to keep it full and oxygen out. After 14 days, the main fermentation was complete (i.e. very little further fall in the liquid-level in the jar) and so I removed the kraut into a storage Kilner jar, using a tablespoon. At first it appeared that there was too much kraut for the jar, and the liquid level was very low. However, due to the finely shredded nature of the cabbage it could be packed down very tightly into the jar using a desert spoon,  and when the jar was full to within about 3 cm from the top, the liquid level had risen so that the shredded cabbage was completely covered. I put the lid on loosely and placed the jar in the fridge.

This is an interesting sauerkraut, crisp in texture and with a mixture of strong flavours, dominated by the garlic, but with an undertone from the caraway seed. The colour is nice too - purple from the effect of the acidity which develops during the fermentation, on the colouring matter from the red cabbage - with orange pieces from the carrot.

This interesting project continues...

(1) This was the initial batch, and I think it was a case of beginner’s luck. I took a savoy cabbage (ca 3 lbs), removed the outer leaves, cut out the core and then sliced the rest of the cabbage fairly thinly, first lengthways then sideways, with a sharp kitchen knife, putting the whole into a large mixing bowl. I then added 2 level tablespoons (ca 40 grams) of table salt (in the U.K. this is chemically pure sodium chloride, and contains no iodine, which it is recommended to avoid) and then worked the cabbage firmly with my hands (first thoroughly washed, rinsed and dried with a sheet of kitchen-towel, which is fairly sterile, while ordinary towels usually have bacteria on them). After a few minutes, the cabbage began to grow wet, and limp, and water started to collect in the bottom of the bowl. I continued with this action, and also by rolling fist-sized chunks of the cabbage between the palms of my hands, to provide a kind of shearing force. After about 10 minutes, the volume of the cabbage had reduced to perhaps one third of the original. I then began to put the cabbage into a quart (1.3 litre) jar, fitted with a lid. I first sterilized the jar, its lid and the square jar (mentioned below) with boiling water. I have noticed that after this salt-workout, the skin of my hands becomes very soft, so perhaps I am sloughing-off some of the surface layers, which may contribute to the final sauerkraut in some way.

Since the quart jar had originally contained pickled gherkins, which were sealed under a partial vacuum, there remained a small slit in the lid, as we had to make in order to equalise the air pressure and open it in the first place. I pressed the cabbage down using a smaller, “square” jar that fitted inside the large one, filled with water to add weight, and closed tightly with its own lid. I then put one of the original outer cabbage leaves over the cabbage and the jar on top of that. By applying pressure, the liquid was forced up, so to cover the cabbage. I then closed the main jar with the lid with the slit in it, which served to vent any gas produced during the fermentation process. To avoid any airborne particles, spores etc. from getting through the slit, I placed a muslin cloth over the lid, which I held in place with a rubber band. 

Well, this was pretty much it, and it was only necessary to let nature do its work, i.e. the lactobacillus (bacteria) to ferment the sugars to a mixture of lactic and acetic acids (“sauerkraut” means “acid cabbage”), plus carbon dioxide. The CO2 could escape from the jar through the slid in the lid, but it also served the purpose of flushing the oxygen from the head-space above the liquid. If the liquid content is insufficient to cover all the cabbage, then it is fine to make a solution of one tablespoon of salt (20 grams) in 400 millilitres of water, i.e. a 5% brine solution, and add sufficient of this until the cabbage is submerged.

After about 11 days in a room with a temperature ranging from about 55-65 degrees Fahrenheit, the sauerkraut was ready to eat, and I used a slotted serving spoon to transfer it to a Kilner jar, which I placed in the fridge, but with the lid on loosely to allow any CO2 to escape, since the product is still fermenting at this stage, albeit much more slowly than at room temperature. It is important to keep the sauerkraut under liquid in the Kilner jar too, to avoid other “bad” bacteria getting in, the consequences of which I shall describe. It tasted very much like sauerkraut that I have eaten in Poland and Germany, so it was the real McCoy. It was, however, very salty to the taste, and I found myself putting a batch of the sauerkraut into a strainer and washing some of the brine away before eating it. This does lose some of the additional flavour though.

(2) I then cleaned out and sterilized the fermentation jar using boiling water and proceeded much as above, but I only used one level tablespoonful of table salt (not two) this time. In addition, I chopped up a whole red onion, and grated a small carrot, which I mixed in with the cabbage, before putting it into the jar to ferment, along with two level teaspoonfuls of caraway seeds.

Due to the high sulphur content of the onion, after a few days, the house began to reek of sulphurous gases (hydrogen sulphide, dimethyl sulphide etc.). However, it is our routine to open all the windows first thing, to get rid of the moist air from inside the house as an antidote to the problem of water pooling particularly in the kitchen and bathroom, but elsewhere too, leading to the growth of mould, and so the smell was soon eliminated. Indeed, since every cloud has a silver lining, the stench from the sauerkraut provided a good indicator of when all the humid air had been exchanged for the fresh air from outside. There was more froth produced this time, presumably because the carrot added additional sugar to the system, some of which was converted to CO2. The product was very tasty, aided by the onion and the caraway seed, and I placed it in the Kilner jar, with the lid loose, in the fridge.

(3) This time, my luck ran out! I proceeded as above, using shredded cabbage, and half a red onion this time (which mitigated the smell considerably), a small carrot and two teaspoonfuls of caraway seed. All seemed to go well, and the product was once again very flavoursome, but I was careless in not keeping the sauerkraut covered with brine, in the Kilner jar in the fridge. The result was that I suffered some diarrhoea over a couple of days, which was not too serious, but I made the mistake of using some of the leavings from this batch to inoculate the next one. This worked very well, but because there was “bad” bacteria growing in it, the entire new batch became infected. Rather than the healthy smell of the previous batches, it smelled “off” (a kind of sweetish, "rotting cabbage" type of aroma), and so I put it on the compost heap. No reason to waste it, just feed it to the garden instead.

(4) I decided to try fermenting a red cabbage. This had a somewhat firmer structure than the white (savoy) cabbage, and so the final product retained some of this al dente quality. The amount of froth seemed greater than with the savoy cabbage alone (Batch 1), and similar to those batches (2 and 3) which contained additional sugar from the grated carrot that I had added. Noticeable too, was that as the fermentation proceeded (over 11 days) the colour became that of a deepening and attractive magenta. This is because the colouring matter (anthocyanins) in red cabbage acts as a pH indicator. Indeed, when cooking red cabbage, I add some vinegar to it, to keep the colour, which is more appealing to the eye. It is the same when cooking beetroot, e.g. in making borscht, to which a couple of teaspoonfuls of vinegar preserves the magenta shade.

As before, I then removed this sauerkraut to the Kilner jar (first sterilized with boiling water) and put it into the fridge. The most noticeable aspect this time was an unusual smell. We puzzled as to what it reminded us of, and after a while we realised that this lactofermented red cabbage smelled of mustard. I imagine that this is from the isothiocyanates that are produced during the fermentation process, of which there must be more in red cabbage than in white cabbage. I have previously extracted the essential oil of mustard by heating either the seeds or the dried powder (English mustard) in the presence of steam (a process called steam-distillation), which is, or contains, allyl isothiocyanate, and it would appear that similar compounds are produced by lactofermentation of the sulphur compounds in red cabbage. I shall repeat the procedure of batch 1, using a savoy cabbage, but using only one level tablespoonful of table salt, keeping my senses keen for the detection of any mustard smell or taste.

Thus, from the red cabbage, we have a very pleasant kind of sauerkraut, with an appetising mustard relish.

(5) I decided to return to simplicity, and ran a batch of savoy cabbage with a couple of teaspoonfuls of caraway seed added. I made sure that the shredded cabbage was fully submerged by adding 400 mls of 4% brine.The difference between the first batch and this is that some white mould grew on top of the cabbage leaf, that I had used to cover the shredded cabbage, and above it in a couple of places, on the side of the jar. I have not noticed this in any of the previous runs, although others have experienced the phenomenon, judging from some of the on-line discussions. I wonder if the warmer weather now might be encouraging the growth of mould? I simply removed the mouldy leaf carefully, and discarded it, along with the top (half inch?) layer of the sauerkraut, onto the compost heap.

This batch is very tasty, and I am making sure that I press it down under the liquid, in the storage jar, after I remove some of it to eat. We have eaten it over a few days now, with no ill effects, and so the procedure of working from scratch, sterilizing all utensils with boiling water first, NOT inoculating the next batch with liquid from the previous one, and ensuring that both during the fermentation stage and subsequent storage, the sauerkraut is kept covered by liquid, seems to work. There is no detectable mustard odour this time, which seems to be a specific feature of fermenting red cabbage. This is probably due to a molecule called sulforaphane which is an isothiocyanate, as I had surmised. It's useful being a professor of chemistry, at times! :-) I started another batch earlier, using just savoy cabbage (I forgot to add the caraway seed, this time!), and we shall see if this turns out OK too. 

(6) I attempted to repeat the above, and my having been away for several days, the batch ran for longer this time. Again, mould began to grow on that covering cabbage leaf, but extended more severely given more time and warmer weather. I removed the leaf, but the mould on it had begun to infect the shredded cabbage below, as was obvious from the "mouldy" smell. I wasn't going to risk eating bad bugs (as in run 3) again, so this one ended up on the compost heap too!

I am pretty certain that the problem is that leaf, which is supposed to act as a kind of seal, and help to keep the shredded cabbage underneath the brine. However, those parts of it that rise above the brine, and are hence exposed to the air, provide a surface for mould to grow on, and so it's time for a repeat, but using extra brine as necessary, and putting the water-filled square jar onto the shredded cabbage directly, to keep it well below the surface. So all in all, 4 out of 6 batches have worked to date.

(7)This batch, using savoy cabbage, has fermented perfectly! Very nice "healthy" smell of acidic cabbage (i.e. sauerkraut). It tastes pretty good too. No trace of mould this time, so avoiding that outer leaf as a "seal" over the shredded cabbage is a good strategy, as is keeping the brine level up.

One point is that as the cabbage fermented, the level of liquid rose, probably due to pockets of fermentation gas which caused the bulk to expand. This, however, was counteracted by simply removing a few tablespoonfuls of liquid, periodically, to avoid overspill.

I had also included the outer leaves, shredded, in the fermentation batch, and so the feel on the teeth is slightly on the "tough and chewy" side, (al dente!), but it is a very edible and flavoursome product.

I think we may have the correct recipe now!

(8) This time, I used a "white cabbage" (no "savoy" cabbage available). I cut it in half and removed the core, then shredded it directly in a large mixing bowl, with a sharp knife, adding one tablespoon (20g) of table salt to it, and worked it with my hands as described before. This time, quite a lot of water came out of the cabbage, and formed a shallow pool at the bottom of the bowl. I also added a teaspoonful of caraway seeds. I transferred the whole lot to the fermentation jar, and covered it with a solution of one tablespoon (20g) of table salt dissolved in 500 mls of water (i.e. a 4% brine solution).

I forced the mass down with the square jar full of water, held that down by putting the lid with the slit on top of the fermentation jar, and covered it with the muslin cloth, kept in place with a rubber band.

This one worked (lactic acid odour) but there was a strong smell of yeast, which is probably not good. Not sure what happened here, but perhaps the batch having stood for 16 days is part of it. To be on the safe side, we decided to put this one on the compost heap. I think that better attention to time, i.e. not leave it more than 11 days.

A couple of thoughts on what might have caused the yeast to grow: (1) I had almost certainly have introduced oxygen when I removed the lid to decant some of the liquid, as the cabbage mass "swelled". Perhaps I should just have left it to overflow? (2) It is much warmer, being Spring, and so the growth of yeast or moulds may be a more critical factor now.

(9) "Pointed spring cabbage" used this time (again no Savoy available), and again just one tablespoonful (20 g) of salt, sprinkled throughout the bulk of the shredded cabbage. There is less material and so the fermentation jar is about 3/4 full, hence there will be no need to remove the lid due to the liquid level rising. I included some of the shredded outer leaves (as in batch 7), and covered the whole to a depth of about 2-3 cm by adding 500 ml of 4% brine. I also sterilized the muslin cloth in boiling water, before putting it over the top of the lid, where it is held in place with a rubber band.

I have made a note of the date, to avoid leaving the fermentation too long this time. I suspect that over a longer time there is a risk of out-competition by other organisms, e.g. yeast!

The batch worked perfectly. Interestingly, there is a pleasant "mustard" relish to it (as when I used red cabbage (4)) and a wonderful "sauer" aroma. The fermentation had run for 11 days, and there was a hint of mould in one place, so I skimmed-off the top half inch or so, just to be sure of avoiding harmful bugs. It really tastes great - probably the best of the batches so far!

(10) Another run with white cabbage, but avoiding covering with a cabbage leaf which attracted mould last time. I shall also leave the whole sealed until I am ready to see how it has proceeded in 11 days time. Under the present conditions, this appears to be the critical time period. Long enough for fermentation to occur significantly, but not long enough for moulds and other nasties to take hold.

I think that white cabbage must be naturally infected with yeast, as once more with this type, after 11 days of fermentation, the smell of yeast was overwhelming. Evidently the yeast can survive the salt water. Another batch onto the compost  heap! I shall avoid trying to make sauerkraut from this sort of cabbage in future.

(11) Another batch commenced, with "pointed spring cabbage".Alas, after 11 days, there was mould growing on the top and even after removing the upper inch or so, there smell was "off". Another batch consigned to the compost heap.

(12) Set off a new batch, using Savoy cabbage, and this time 40 g of salt (as in batch 1), hoping this will allay any mould or yeasts that might be floating around.

Hmmm... alas, mould clearly growing after just 3 days, and a very strong smell of "rotten cabbage". I am assuming that there is a lot of mould floating around - damp conditions and warm, with in being almost summer. Another batch on the compost heap!
50:50 success rate so far, with most of the trouble occurring during these more recent wet, humid months. Making sauerkraut is definitely easier during the winter!

Seems the mould problem is being experienced by others too, from what I can read on-line. Also the lids of the main fermentation jar and the smaller "weight" square jar are becoming rusty, a process that is worsened by the salt.

(13) Tried another batch, this time of red cabbage. Used 2 tablespoonfuls of salt, to work the cabbage with, and filled the fermentation jar up to within 2 cm of the top (to minimise any oxygen content), with brine [one and a half tablespoonfuls of salt (30g) in 500 ml of water]. No square jar (weight) or intact cabbage leaf on top of the shredded cabbage. Left it to ferment for 10 days. There was some mould (looked like jam-mould) and white scum on the top, but restricted to the surface.

Removed the upper 3 cm of the cabbage, and discarded it onto the compost heap. As before, there is the hint of mustard both in smell and flavour, and this batch looks OK.

So, the "trick" of filling the jar almost to the top to keep the air/oxygen out, seems to have worked.

the sauerkraut into the storage Kilner jar, in the fridge, making sure that it is well covered with the brine, which, as last time, has turned a rich magenta colour.

Have been eating the suaerkruat for several days with no ill effects, and it is delicious. I am wondering if, in addition to keeping the air space volume low, the red cabbage and its isothiocyanate compounds actually discourages the growth of yeasts and moulds?

Now this was just a hunch, and I have now done a bit of research into the matter. Indeed, it has been long known that isothiocyanates are highly active in retarding the growth of fungi
including yeasts

(14) Ran another batch of red cabbage, which worked well too. There was a sight rotting ("off") smell on opening the jar, from cabbage that had risen to the surface and was above the brine layer, but having removed the top inch to put on the compost heap, the rest is delicious, with its usual healthy acidic aroma and taste.

No surface "jam-mould" this time either.

(15)  I have just set-on another batch of red cabbage, to see if we have the recipe right now. 2 tablespoonfuls of salt used for the kneading process, and the cabbage shredded somewhat more finely than in previous batches, which caused more of the (red) liquid to be drawn out . Placed in the fermentation jar, and topped up with 4% brine (20g of salt in 500ml) to an inch from the top.

Lid on and covered with muslin cloth, held in place with a rubber band.

Another dud, I'm afraid! Loads of mould had grown, mostly at the top, but on pouring the whole lot onto the compost heap, it was obvious from the white scum at the bottom that the mould had taken hold right through the cabbage. It appeared that the finely cut cabbage had upwelled, in a process known appetizingly among the sauerkraut-making community as "heaving". The effect is due to fermentation gases making the bits of cabbage bouyant, so casing the mass to expand.

This would have brought a significant amount of the cabbage above the brine layer, where mould could grow. However, in the last two batches, which were fine, there was a layer of cabbage above the brine but no mould at all in one case, and just the surface "jam-mould" in the other. Not sure exactly what's happened this time, but I have kerned that making sauerkraut is as much an art as a science.

(16) OK, have put another batch of red cabbage on, but made every effort to (1) minimise the oxygen in the jar, and (2) keep ALL the cabbage underneath the brine.

Red cabbage chopped, and worked with 2 tablespoonfuls of salt. Far more liquid came out this time than in previous runs. All added to the fermentation jar. Two outer cabbage-leaves put over the chopped cabbage, but weighted down with an inverted "flat" jar (4 cm in height, and 8 cm in diameter). Jar topped right to 1 cm from top with 5% brine. Any floating bits of cabbage were removed. The level of brine is about 5 cm above the cabbage-leaves on top of the chopped cabbage, which should protect it all?

Fresh muslin cloth over the top, held in place with rubber band. As this muslin was a bit wide-holed, I have put a piece of kitchen towel underneath it, to help keep out any airborne moulds.

This strategy seems to have worked a treat. No trace of mould or anything else nasty, Just good tasty sauerkraut. It has also kept well in the fridge in a Kilner jar, while we were away for a week.

(17) Trying the same principle with a pointed spring cabbage. Cabbage shredded and worked with two tbsp of salt. Put into fermentation jar. Actually quite a small cabbage and so it only filled one third of the jar. Put one of the outer leaves on top of the shredded cabbage, but in a concave-side down fashion, and then two inverted shallow jars on top of that to fill the headspace. Then poured 750 mls of 5% brine into the jar to fill it to within 1 cm from the lid. Lid on and piece of kitchen towel, followed by two pieces of coarse muslin placed over the lid, with all three layers secured with a rubber band.

There was some slight overflow of liquid from the jar, which soaked into the muslin cloth, giving it a rusty colour presumably from the slightly corroded lid, with the brine in contact with it, and kitchen towel, but no harm done.

This batch worked wonderfully, with no mould at all, and a delicious "sauer" aroma. It tastes delicious. So, keeping the air space to a minimum (zero, in this case) and all the cabbage kept well under the salt solution is the key to successful sauerkraut production.

One interesting, and for a few minutes rather confounding point was that although I had managed to put the two empty jar inside the main fermentation jar, inverted and on top of the intact cabbage leaf to hold all in place and prevent heaving, while the first one came out OK face-down, the lower one would not come out end-on! I racked my brains for a while, feeling a little as though I was in an episode of the Twilight Zone, as surely I thought, the diameter is the same face-down or end-on, but of course, the effective length is only equal for both situations at the central point, i.e. if the depth of the jar being inserted were close to zero.

For a real jar (depth 4 cm), the effective length of the larger jar becomes smaller on moving away from its centre, so that the jar one is trying to insert or extract, end-on, is too big to get in or more pressingly, out! :-)

(18) Following the success with the last batch, I have decided to go for broke and try fermenting a white cabbage. You may note that all such attempts so far have failed with this type of cabbage, due to the overgrowth of yeast, as can be smelt profoundly on opening the jar! Perhaps the compost heap will be denied its dinner this time! :-)

Yes, a perfect result!! After 12 days, the healthy and gentle "sauer" aroma was extremely pleasant, as was the taste! The sauerkraut had a quite soft texture this time, and there was the hint of mustard to the smell/flavour. I had filled the fermentation jar with (4%) brine up to 1 cm from the top, and held down the shredded cabbage by placing a couple of intact cabbage leaves over it, all weighted down with a single inverted jar, which could be removed easily once the work was done. I put two layers of kitchen towel over the lid, and a couple of pieces of coarse muslin over this, all held on with a rubber band. The cloth/paper towel was damp, which showed that the liquid had overflowed to some extent, through the slit in the lid, due to "heaving" as the fermentation proceeded.

However, this meant that there was no air space, and so nowhere for yeast/moulds to grow. The latter seem to flourish where there is a significant brine-free space and oxygen present. Filling the jar up with brine, nearly to the top, avoids this.

I put the muslin pieces into a glass jug and covered them completely with boiling water, to kill any nasties that may have been growing on/in the wet exposed material.

(19) In view of the success of the last batch, I am running another batch, this time of pointed cabbage (also known as "sweetheart cabbage") exactly as in (18). There were no white cabbages left in the shop! Hopefully next year, we will have cabbages from our own garden!

2 tbsp of salt were added to work the cabbage with, which withdrew a fair amount of liquid. Then 1 tbsp of salt dissolved in 500 mls of water (4%) poured into the jar, plus sufficient water (about 50 mls extra) to bring the liquid up to within 1 cm of the lid. Before adding the brine, I squeezed a large outer leaf over the shredded cabbage, with none of it entering the small air space. I have placed the inverted small jar on top of the large leaf, to weight it all down. Most likely the air space will fill as the brine level rises due to heaving as the fermentation proceeds, so any stray "ends" of the leaf will remain under the brine and out of contact with air/oxygen.

Even after 2 days, the paper/muslin cloth is damp, which shows that the fermentation/heaving has begun in earnest, and excess liquid is leaking out of the slit in the lid. It occurs to me that the salinity of the liquid will probably prevent moulds or yeast growing on the paper/cloth, and all the more so during the fermentation period, because the salt concentration will increase as the liquid is increasingly absorbed and evaporates.However, maybe leaving an inch (2.5 cm) as a head space depth, rather than just 1 cm is a better strategy, to avoid too much overflow.

Hmmm, curious outcome. Although the cloth remained wet for about 8 days, it then dried. So today (day 11) I took the lid off, and it appears that the liquid level had fallen to about 3 cm from the top. I can only assume that the heaving cabbage as it fermented continued to displace fluid out of the top of the jar, but then there must have been a "settling" of the chopped cabbage or the covering leaves, to occupy less space. The covering leaves were actually above the liquid level. No obvious mould though, but I have removed the upper inch to add to the compost heap to be on the safe side, and the rest of it was absolutely fine. Very tasty and with no harmful effects.

(20) Same technique as in (19) but with a savoy cabbage. The latter chopped finely, and worked in the hands with 2 tbls. of salt. The whole reduced in volume to about one third of the original, which I placed in the fermentation jar, previously sterilized with boiling water. Put one of the outer cabbage leaves over the chopped cabbage, then added the inverted shallow jar as a weight, and topped the whole lot up with 4% brine solution (20g salt in 500 mls of water), to within 2 cm of the top. Then screwed the lid on. 2 layers of kitchen towel and a couple of layers of muslin cloth over them, all held in place with a rubber band.

Fermentation visible within hours (bubbles), and the towel/cloth became wet within 24 hours, showing that the heaving process had displaced the liquid so that the jar was full, and obviously overflowing to some extent through the slit in the lid.

This will keep any oxygen out and all the cabbage under the brine layer. So far this has produced a healthy and flavoursome sauerkraut, and so I am hoping for a similar result this time too! I note that the last 4 batches have been fine! :-)

[I am also thinking that as the overflowing salt water, which is absorbed by the paper-towel/cloth, evaporates, the concentrated salt that it leaves there, will prevent anything nasty, i.e. moulds or yeasts from growing, and act as a barrier to infection of the kraut, even if the liquid level drops back during the fermentation to recreate some air-space].

Voila! After 12 days fermenting, we have a wonderful, aromatic (if you like the smell of sulphurous compounds!) sauerkraut. In the storage jar, in the fridge now. So, the technique has worked successfully for the last 5 batches.

The taste is really good, too!

(21) Repeated (20) using a savoy cabbage, and another success - the 6th in a row!

(22) Repeating (20), again using a savoy cabbage, which seems to be all there is in the local store these days! :-) I am pretty confident that this will work with all types of cabbage and maybe other kinds of vegetable.  Worked a treat. Absolutely delicious "sour" smell and taste - the 7th in a row!

I am thinking that now the weather is much colder, the growth of yeasts and moulds will in any case be discouraged. However, some of the earlier batches, run in early March did get infected and so I have confidence that it is the new technique that these good results are mainly due to the new technique.

Another batch of savoy cabbage running now, with a teaspoonful or so of caraway seed added to it. Another success (8th in a row). Heavy flavour of caraway this time.

The only problem is that the steel lid on the fermentation jar is beginning to corrode quite badly, presumably because of its contact with the salt-solution, particularly when the cabbage "heaves" during its fermentation and some of the liquid is displaced, as noted.

(24) Another run of savoy cabbage alone (2 tblsp of salt used to work it with). No lid on the fermentation jar this time, but instead a food bag placed sideways on as a plastic sheet to cover it (1 cm slit made in it with a knife), and the two layers of kitchen towel, and two sheets of muslin on top, all held in place with a rubber band.

I have set the jar in a bowl in case of any overflow.

The liquid level dropped after about day 7. I did top the jar up to about an inch from the top after day 10, but it fell again. Opened after day 12 and there was a very fine mycelium growing on top of one of the covering cabbage leaves which the liquid level drop had brought above the surface. To be on the safe side, I removed the top inch of sauerkraut below it and put it onto the compost heap. 

Have been eating it for a couple of days with no side-effects. The flavour is wonderful (slight mustard). I think, as usual, the trick is to keep that liquid level as near the top as possible and any leaves fully submerged.

(25) Essentially a repeat of run (24) but with the cabbage shredded very finely: cut in 2 mm widths, then cut crossways as finely as possible, although this is difficult as the cabbage begins to fragment as it is cut.

It is November the 8th and wow, that cabbage is COLD to work with the hands! Red fingers, like when playing snowballs when I was a kid. :-) Shredded cabbage in jar, and topped up with brine (1 tblsp of salt in 500 mls of water). Shallow 8 cm wide inverted glass jar used as a weight on top of the covering leaf, which this time I have put 4 slits into, at respectively 2 cm from the stalk of the leaf and 3cm from the outside of the jar to help let fermentation gases out. I am hoping this might help to reduce the sporadic liquid level problem. Sufficient tap-water added to bring the final liquid level up to 1 cm from the top of the jar.

Again, no lid on the fermentation jar this time, but instead a food bag placed sideways on as a plastic sheet to cover it (1 cm slit made in it with a knife), and the two layers of kitchen towel, and two sheets of muslin on top, all held in place with a rubber band.

Some overflow, but all caught in the dish. Needed topping-up with brine after about 8 days. This has prevented any mould growing this time.A perfect batch of sauerkraut! Slight mustard and  "heathy" sulphurous smell/taste.

(26) Same as the last one, but with one difference, that I sliced the cabbage as finely as I could, and finer than for any of the previous batches. It has been in the storage jar in the fridge for perhaps 7 days. And it is DELICIOUS!

The sauerkraut has formed a soft texture, and it has an amazing mustard plus sour taste! The flavour seemed to improve over a week or so in the storage jar, in the fridge, and the kraut softened.

Without doubt, this is the best yet! ...the trouble is I'm not sure precisely why it has turned out so well? I am suspecting that it is the fineness of the cabbage that has mad the difference. By shredding it as I have done, the surface area is much larger, so assisting access to the nutrients by the lactobacilli.

I am currently doing a permaculture design course, which emphasises the importance of "edges", as being the regions where most activity occurs. Thus, I have created more edges and so the cabbage has been more worked-on/fermented.

(27) Another batch on, equally well-shredded, and so let's see if it tastes as good as the previous one.

Crisper in texture this time, but a smell of hydrogen sulphide when I took the top off. Skimmed off the first inch of kraut from the top, to be safe, and then the more usual "saur" smell was evident.

This one remained on the crunchy side, but did improve in flavour over the couple of weeks it was kept in the fridge.

(28) Used two "sweetheart" (pointed) cabbages. " because they were rather small, and not as tightly "packed" inside as the savoy, or the white cabbage.

Slight white film floating on the top this time, just in the centre, about 2 inches across. Removed this with kitchen towel, the two leaves on top of the "kraut" and the top inch, all food for the compost heap. Odd slight "apple" smell, which oddly disappeared once the kraut was transferred to the storage jar and had been in the fridge for an hour or so.

This time the flavour was strong, almost "meaty", but I rather like it. It goes well with the salt-taste! Different taste from batches (9) and (19).

It is remarkable how the various batches differ from one another. 

(29) Have changed the inverted jar that acts as a weight on top of the intact outer cabbage leaf to hold the shredded cabbage down, to a larger and slightly deeper (and therefore heavier) jar. It worked well. The effect of "heaving" during fermentation does still raise the inverted jar and so an air-space is created probably when the kraut settles again. So, a jar filled with water is now place on top of this, over the paper and cloths, to hold it down.

Rather than fermenting for 11 days, as I did for most of the earlier batches, which produced a "crisp" kraut, if the process is left for 14 days, a rather softer texture results, which we prefer. So, the fermentation-time can be adjusted according to taste.

I also attended a short course on fermented foods run by Annie Levy at the Reading International Solidarity Centre (RISC), last Saturday (7th March). This was part of the Permaculture Design Course, run by Steve Jones of Sector39, over six weekends at RISC. That was weekend 5, and we have to produce an actual design for the final installment in a fortnight's time.

Annie gave me the opportunity to demonstrate my technique for working a shredded cabbage into sauerkraut and made a short video of me in action: So, these same "strong hands" processed another (savoy) cabbage yesterday morning, which is working its mojo as we speak!

(30) Repeated the above procedure, and left it to run for 14 days, Once again, a really tangy, soft kraut was produced.

By the way, the PDC was completed last weekend, which left us all with mixed feelings. On the one hand, the course was wonderful, and so we will miss our alternate weekends learning abut permaculture, and yet it feels like the start of a new phase. Nothing for it, but to put our permaculture design into practice, and wait for our certificates to arrive! :-)

(31) This time I used a white cabbage. Chopped the cabbage as finely as possible, using just one tablespoonful of salt to work it. The outer leaves of this kind of cabbage are quite stiff, and so I fitted this over the chopped cabbage, and topped it all up with brine (1 tblsp in 500 mls of water, rather than the 2 tblsp I had used in most of the previous batches). I didn't put the inverted jar on top of it as a weight, as it has proved a bit difficult to extract, and I closed the jar with a plastic food-bag, with a slit in it, a couple of pieces of kitchen towel, and two layers of muslin cloth. I held the whole in place with a couple of tight rubber bands, and set the jar in an earthenware dish to hold any overflow.

Let's see how this one gets on! My typical fermentation-time is 14 days now (up from the original 11 days), which seems to give a good, soft, tangy kraut.

Yes, another success. Compared with the Savoy cabbage, this gave a kraut with a slight mustard relish. It is absolutely delicious!

(32) Another batch on, this time with a Savoy cabbage. One tblsp of salt used to work the cabbage, a large outer cabbage leaf put over the chopped cabbage, and the whole lot  topped up with brine (1 tblsp in 600 ml of water). Absent mindedly, I did put the small inverted jar on top as a weight this time.

As usual (now), I have placed a plastic food bag over the top, with a couple of layers of kitchen towel, and two pieces of muslin cloth. I have found a couple of tight rubber bands which hold everything in place, and stop the jar etc. from rising. This is another innovation!

Because there is a lower salt concentration in this batch (only 1 tblsp used to work the cabbage) I am keeping an eye on the liquid level. THE trick to avoid contamination, I have learned, is to keep the jar topped up as far as possible. Now, the batch has begun to ferment and the dish in which the jar is standing has overflowed into it.

OK, I have poured this down the sink, taken the top off, sprinkled salt onto the inverted jar (which is almost as wide as the hole in the fermentation jar, so it is is bit difficult to pour water into the jar to top it up), and carefully poured water onto this. so that it dissolves the salt and runs into the jar. So, the liquid level is practically back to the top again.

Food bag, kitchen towel sheets and muslin cloths now back on, pulled down tight against the top of the jar, and secured with the tight rubber bands. I will watch for any overflow, topping the jar up as necessary with water to keep the air out, and the same if the kraut settles so bringing the liquid level down.

The whole fermented wonderfully, and the kraut was so tasty that I hunted out another, and very large, white cabbage to run another batch.

Even with the warmer weather which had previously thwarted my sauerkraut attempts, and white cabbage being especially vulnerable to yeast infections, I have had no problem using the method I now use.

So, I keep an eye on the liquid level and simply take the "lid" of and top it up practically to the top of the jar when it falls. Soemtimes I sprinkle some more salt in to keep the brine concentration at an adequate level.

The smaller inverted jar only just fits inside the larger fermentation jar, and so topping the level up takes a little care and generally I pour the water onto the inverted jar and let it trickle down the sides to raise the overall liquid level.

Really, this is the key trick, to keep the air/oxygen out and make sure that there is no shredded cabbage, or the intact leaf that I put over it to hold the finer material under the liquid, exposed to the air.

This has proved to be the failsafe mechanism!

 Usually only one tbsp of salt is required to work the kraut, unless the cabbage is very large.

(33) Large white cabbage processed as described, and two tbsp of salt used to work it before fermentation. 

Again, it has worked fine and even with the warmer May weather, there is no trace of mould or yeast as in the batches that I ran this time last year. So, keeping the jar topped up with liquid is the key.

This time, the kraut is quite al dente, and it is quite interesting how variable the different batches can be, even when they are ostensibly identical. I wonder if the larger size of the cabbage correlates with a tougher structure? Due to the large size, however, the product needed two of the normal sized Kilner jars to store it in, and a bit more fridge space

(34) This time used pointed ("sweetheart") cabbage. This is a much "looser" kind of structure compared with savoy or white cabbage, and so I used 2 of them to fill the fermentation jar sufficiently. Cut up finely, including the outer leaves, and put into the fermentation jar, as in the last batch, with one outer leaf over the kraut, and the inverted jar on top of that as a weight.

Keeping an eye on it. Topping it up with water as necessary to keep all the cabbage protected from the air. Draining off any overflow, as the kraut upwells and settles again as the fermentation proceeds.

It is necessary to monitor the liquid level almost daily, as the kraut does settle as the fermentation proceeds, so creating an air space, which needs to be filled with water. The occasional upwelling occurs too, so the liquid spills over a little, but this is caught in the dish that the fermentation jar stands in.

The batch is excellent, with a wonderful "acidic" aroma and taste, actually a bit like vinegar! The consistency is quite "soft".

It is now almost the end of June and hot, but no moulds or yeasts have troubled us, as yet, this year, so I think that the method we are using is now sound!

(35) As before, but needed three "sweethearts" as they were rather small. But, it is now August 30th, and we have still had no problem with moulds or yeasts


Scharlie said...

Very informative, Chris! And laborious...
It sounds delicious, especially your last batch from the red cabbage... alas, I am lazy and I buy (in bulk) Tescos Sauerkraut (in the world section, comes from Poland I believe) which seems less work.... Saurerkraut is delicious and very very healthy, as you probably already know. I even mix it wit spaghettis or make Sauerkraut Lasagne....From the historical point of view: Traditional Chinese has long prescribed sauerkraut juice as a home remedy for many common ailments . The armies of Genghis Khan most likely first brought the dish to Europe. The Roman army traveled with barrels of sauerkraut, using it to prevent intestinal infections among the troops during long excursions.

Chris Rhodes said...

Hi Scharlie,

as you can see, I have had my successes and failures too, but at least I think I have the method right now!

I can go on and try variations of it, and work on to fermenting other kinds of vegetables.

There are many Polish people living in reading and so Polish shops that sell sauerkraut, BUT as I say it is pasteurised so that's no good.

Interesting what you say about it's history, and I was told by someone who is an expert on nutrition that were it not for saurekraut, many people would have starved in northern Europe in days past!

Anonymous said...

Hi Chris,
Just so you are aware, there is a company called GLK Foods. They are in the process of introducing a Raw & Natural sauerkraut to the market that will have a vent to let the gases escape. All probiotic bacteria will be alive and kicking in this product. From what I have heard, it will be coming in a variety of flavors as well as the classics, like sriracha, wasabi and Dill & Garlic.
Keep an eye out for it!

Chris Rhodes said...

Thanks for the information - I shall keep an eye out for this company.

I shall also continue with my own experiments, which are great fun!

Rod Bilton said...

Hi Chris,
You never do things by halves! Soon you will have the perfect microbiome. I've been making ferm vegs for the past year and am amazed how long the products stay fresh and edible.I kept some red cabbage and carrot krauts for 6 months and they still tasted delicious and did not cause stomach upsets. My initial expts using glass or rigid plastic vessels were not very successful with frequent mold contamination. As you say oxygen is the main problem. I have overcome this by using sealable plastic bags which enable the removal of all the headspace air. Samples can be removed with tongs to squeeze out the excess liquid and the bag resealed having squeezed out all the headspace gas/air. I've never had any more contamination since using this method and have been able to drop the salt to one tablespoon per Kg of veg. I've had particularly good results with red cabbage, carrot, beetroot and celeriac is particularly delicious. I use the same rapid routine for all the vegs- an old food processor set on fine shred cuts down the time needed to massage the veg and salt. Another tip is to add 1-5% inulin to stimulate growth of the right bugs.Finally, try and get some fresh turmeric. When fermented it makes an excellent healthy condiment.

Professor Chris Rhodes said...

Hi Rod,

glad you have found my blog, and these adventures with sauerkraut which I have been making and eating for about 2 years now. I do use a rigid glass jar for the fementation, but the trick seems to be to keep it as full as possible, just by topping it up with water daily, and I haven't had a batch go bad (either from mould or yeast) for a good 18 months now!

As you say, all kinds of vegetables can be lactofermented, and they do keep well.

I like your idea of using re-sealable plastic bags too. I use about half the amount of salt that I did originally, so also 1 Tbsp of salt (ca 20 g) per cabbage, i.e. about 1 kg. Another method we use is to do the fermentation in a kilner jar, but with the lid on loose, so that the gas can escape.

My original reason for eating sauerkraut was that I developed a touch of IBS, read that probiotics could help, and that sauerkraut was packed full of them, so long as you made it yourself rather than the pastuerised version that can be bought. I must say that I have had very little such trouble since making and eating sauerkraut regularly.

I will try adding inulin, as you suggest, and as I am about to put on another batch today, will use turmeric instead of my more usual caraway seed!

Here's to our collective happy further adventures in the world of fermented-veg!