Anything I’m Fermenting

October 4, 2008

Soy Sauce…6 months later

Filed under: Soy Sauce,Tasting — iwouldntlivethere @ 10:43 pm
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Yes, it has been half a year since I started making the soy sauce. We’ve been using it often – haven’t bought soy sauce in months! I often railroad any guests we have over into trying the soy sauce; the general opinion seems to be that it tastes good, but is very salty, and is different from regular soy sauce.

The sauce has gradually darkened – I have a tub of it that we are working through, but I pour off some into a more practically sized bottle for everyday use, and have noticed the change. Originally, I tended to only use it when cooking, but now use it in salad dressings, etc. where it is not cooked, and it tastes good. (more…)

May 15, 2008

The on-going soy sauce controversy…

Filed under: Brining,Lactobacillus,Soy Sauce — iwouldntlivethere @ 4:30 pm
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A couple of new issues have been brought up by Tadaki- is sea salt saltier, the same as, or less salty than regular salt? I really don’t know. I thought it was saltier, but Bittman claims the opposite. Considering he is a chef, cook book writer, and columnist for the New York Times, I’m going with him…for now, regardless of Campbell’s Soup’s marketing. In the end, I added a bit of water to the mash to dilute the salt, and it does taste more like regular soy sauce (in terms of saltiness) now.

Inigo suggests that: “I’d be concerned with the acidic taste, which shouldn’t be happening“. I just tasted it again, and perhaps I have over-stated the acidity. Comparing it to Kikkoman, they are fairly similar in acidity. I agree with Tadaki that the acid taste is likely from lactobacillus, and therefor not really anything to be concerned about. In fact, my original salinity was chosen to promote lactobacillus (among other micro-organisms) fermentation.

As to the aerobic vs. anaerobic question…well, I only really properly tried to aerate it when I first brined the dried soy patties. This was because in beer making, good aeration is needed initially (and only initially) to get the yeast to grow and multiply. After that you try to avoid exposure to oxygen to prevent oxidization (produces off-flavours). With the soy, after the initial shaking-up to aerate the mash, I have only stirred the mash fairly regularly, but not too vigourously, so a bit of oxygen was likely added, but not much. Transferring to the glass jar probably re-aerated the mash, but then all salt I added probably killed off most of what was growing in the mash. Taken together, all this means I probably have something like the ‘microaerophillic’ conditions described in that patent Tadaki sent:

The purpose of these intermittent aeration steps is essentially accomplish in the fermenting Maromi a microaerophillic condition, i.e., a state of oxygen tension that is less than atomospheric and being on the border between aerobic and anaerobic conditions. As can be appreciated from the above, the initial fermentation can be under either anaerobic or microaerophillic conditions, but microaerophillic conditions are preferred. Microaerophillic conditions, at least for part of the fermentation time, develop a superior full-flavor and full-body soy sauce.

I have also noticed that after handling my soy sauce, I can have a fairly stong fish-sauce like smell on my hands – just like after handling a bottle of fish-sauce. This echoes what canucklehead found on tasting his uncle’s home made soy sauce.

May 7, 2008

Long-Winded Soy Sauce Update

I’ve been digesting what Kikkoman said to Inigo for a few days now, as well as what Takadi has asked (sorry about not responding earlier…it has been busy!).

Kikkoman initially says: “we suggest that you use 30 g of salt per 100 ml of water used”. In other words, 30% salt (by my weird calculation) or about 23% by weight.

Then they say: “it is recommended that you use at least 15 to 16% salt, otherwise the moromi mash could decay”.

This made me panic a bit, as my salt concentration, by weight, was only 6.25%! The fermentation has been producing a fairly strong sour smell (or as my wife described it, ‘cheesy’). This is most likely from a vigorous lactic acid bacterial fermentation. As I have mentioned earlier, it was re-forming a pellicle every day (which I would break apart during stirring).

So, I drew off about 800 ml of brine and boiled it with 350 g of salt. As not all the salt was dissolving, I added probably about 200 to 250 ml of fresh water. This I then added back to the fermenting soy sauce, raising the total salinity to about 15.2% (by weight – as you may have noticed, I have stopped using my odd way of measuring salt %!).

I have definitely killed off any visible microbial action now! And it obviously tastes very salty now – in fact saltier than my Kikkoman soy sauce. On the other hand, it does not taste bad at all – it is kind of like a mix of miso and soy, with some extra acidy. Or something like that anyway.

This brings me back to my ‘back of the envelope’ calculation of the salinity of the Kikkoman soy sauce. I have to swallow my pride and say that my memory of chemistry is abominable! Here’s what I said: “My guess is not enough to bring my figure up to 25% though – chlorine is much smaller than sodium, and even if they were the same size, it would double the salt concentration to around 14%, still far from 25%“. Wrong. The atomic mass of sodium is 22.99 g, and chlorine’s is 35.45 g – or over 150% larger! Recalculating the salinity meant going back to the label to see that there were 920 g of sodium in 15 ml of soy sauce. This is actually 6.1% sodium, there would thus be 6.1% + (1.5 x 6.1%) salt, but wait, salt water is denser than fresh water. Again taking a short cut (this will probably end up haunting me later), I found that regular sea water (3.5% salt) is about 2.8% denser than fresh water, and dead sea water (33% salt) is about 17% denser. I just used the average – so I estimate that the soy sauce is about 10% denser than fresh water.

Getting back to the question at hand – this means that Kikkoman’s sodium % was about 5.6% (920g / (1.1 x 15000ml)), so the salt concentration must have been around 14% (5.6% + (1.54 x 5.6%)). Ah Ha! Kikkoman may have been giving Inigo some funny numbers… 14% salt is WAY less than the 23% they recommend, and perhaps even below the level at which they claim the moromi mash would decay (remember, my calculations are not exact)! Maybe they dilute their soy sauce prior to packaging? Maybe European soy sauce is much saltier than North American?

And back to my observation that my 15% soy sauce is noticeably saltier tasting than Kikkoman’s (although not so much as to be unpalatable). This is especially interesting as I use sea salt. Mark Bittman*, in “How to Cook Everything Vegetarian, states that sea salt tastes less salty than table salt. Hmmm…that means that my soy sauce’s salinity may be higher than I calculated, or Kikkoman’s lower. I think it is likelier that my soy sauce’s salinity is higher, as I have not been measure the volumes of water I have removed or added very accurately, and further, water has evaporated over the past few weeks.

Switching gears, takadi asks:

I think it’s interesting you mention the differences between chinese soy and japanese soy and compare it almost to the differences between an ale and a lager. Perhaps that’s why Chinese soy sauces tend to be more robust and Japanese soy sauces more delicate. Would the ratio of wheat have anything to do with the fermentation process either?

I’m really not a connoisseur of soy sauces – this whole experiment has been an eye-opener. As you say, it does sound like Chinese and Japanese soy fermentation styles differ in a way like ales and lagers do. However, I cannot really say much further, as I don’t know the differences well.

The wheat is a bit of a wild card for me, in terms of its effects. I think that in traditional soy sauce making, wheat flour provides a good innoculum source for wild yeasts, lactic acid bacteria, and molds – all of which grow naturally on wheat grains. Without a reliable source of starter/innoculum/koji, farmers may have had to do with what was available. Further, wheat is likely a source of easily assimilated carbohydrates for the molds to feed on, before they are able to attack the soy beans. Unfermented soy beans are not easily digestible by humans, and it may be the same for micro-organisms. Once a culture of micro-organisms has been developed, it is likely that they are adapted to eat pure soy beans, no longer requiring the initial availability of wheat. The wheat may also make it easier to form the loaves. Finally, the wheat may survive to the fermentation stage, providing sugars for yeasts and bacteria to produce alcohol and acids, which creates ‘sanitary’ conditions inhospitable to less desirable micro-organisms. Early farmers lacked access to sanitizers or preservatives, making this last point important.

When you talk about percentages of salt, do you mean percentage of salt in the brine, or percentage of salt total including all the other ingredients?

Good point. Sometimes one, sometimes the other. My own brine was calculated ignoring the other ingredients, while my calculations of Kikkoman’s salinity include the other ingredients (I don’t know how much they weigh). I don’t feel like revisiting my salinity calculations right now, but I may later.

It seems as if this method relies on wild yeast strains similar to creating sourdough starter. How would effect the flavor?

Yes, this method does feel a lot like making a sourdough starter. As I mentioned in the first post, the soy patties initially smelled like my failed sourdough starter (it turned into a salt-risen bread starter). Salt-risen bread is fermented by clostridium bacteria. It makes a very cheesy tasting bread, so perhaps this has contributed to my wife’s opinion that the soy sauce fermentation smells cheesy. The cheesiness probably also comes from lactobacteria. Last weekend I tried a local brewery’s sour beer (fermented partly by lactobacteria) and it smelled cheesy. It was (personally) very over-soured – although very nice when diluted with their lager by 2/3.

“I’m also wondering how tamari is made without the addition of wheat to aid in the process of inoculating a culture.”

I really can’t say. As I say above, perhaps when a starter culture has been used for a while, it adapts to its conditions and is able to digest pure soy.

“…how do you keep the loaves warm in order for the strains to take hold?”

I kept them on top of my fridge, where it is a bit warmer. I don’t think you need to worry much about mold taking hold on your soy patties! 😉 As children discover in their school lockers and at the back of fridges, most foods get moldy sooner or later.

“Do you think keeping the mixture inside an open glass jar would be a different environment than keeping it in a plastic tub? There would definitely be more sun exposure.”

I do think it would give more sun exposure, which by definition is a different environment. In fact, my grandmother just gave me a huge glass jar, and I have transfered the soy sauce into it. As the jar is much smaller than the bucket, I could bring it inside and fit in the window. Besides, you can see what is going on much better. It also seems somehow more ‘respectable’ when it is in a glass jar, rather than in a bucket!

* Bittman’s cookbooks are the only ones I use regularly. Incidentally he has a blog at the NY Times, in which he posted a link to canucklehead’s soy sauce making directions – way to go canucklehead! – around the same time I was starting to make soy sauce.

April 30, 2008

Salty Language!

Filed under: Brining,Soy Sauce — iwouldntlivethere @ 2:14 pm
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Inigo, from Umami Madrid sent me a truly fascinating email a few days ago, explaining that he had contacted Kikkoman Europe about how much salt to use. With his permission I have posted the exchage, starting with Kikkoman’s initial response to how much salt to use:

Dear Mr. Inigo Aguirre,

First of all, we thank you for your inquiry and your interest in making soy sauce by yourself for educational purposes.

As per your inquiry, I’m happy to reply although this may not be enough information to you.

It all depends on what kind of soy sauce (salty, light, etc.) you intend to make, but we suggest that you use 30 g of salt per 100 ml of water used.

I hope you will find a way to make it successfully.

Best regards,

Takehito Kubo

Kikkoman Trading Europe GmbH

So Inigo replies:

Dear Takehito,

Thanks very much for your info and kindest help. I have been using 25 g of salt per 100 g of water, so I think it will be fine.

One…actually two more questions:

What is the minimum amount of satl that could be used (e.g. for light soy sauce)?

Do you use wheat for the soy sauce or is flour just as good? I understand that Japanese soy sauce is done with whole toasted wheat, whereas Chinese soy sauce is done with wheat. Is this so?

In case you’re interested please click on my blog to see how I’m doing it (sorry, it is in Spanish).

Thank you very much. Best regards,


And so Kikkoman replies again:

Dear Mr. Inigo Aguirre,

Thank you again for your inquiry.

For your information, it is recommended that you use at least 15 to 16% salt, otherwise the moromi mash could decay.

Furthermore, we use whole wheat as an ingredient to be roasted.

For general information, please find attached the process of making naturally brewed soy sauce.

I hope this information can be of help.

Best regards,

Takehito Kubo

Kikkoman Trading Europe GmbH

April 22, 2008

Soy Sauce Part 3: Brining

Filed under: Soy Sauce — iwouldntlivethere @ 3:36 pm
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Step 9: Make brine solution. I ended up using a solution of 3 liters (or 3000 g) of water with 200 grams of salt. This is a 6.7% salt solution*.

Step 10: Ferment soy chunks in brine for a few weeks. My fermentation took place in a food-grade plastic bucket, covered loosely by cling wrap held in place with an elastic. It is placed in a large west-facing window in a room that heats up considerably in the afternoon**. I try to stir it once a day. I have noticed that the soy chunks stayed whole for a few days, before breaking down, although a few are still fairly whole. Initially the fermentation produced some bubbles, but that stopped after the first few days.

The fermentation does not have a strong smell as it is partially covered. Even when open, during the first week it had only a mild, fungal smell like freshly cut button mushrooms. After about a week the fermentation formed a pellicle – a bacterial/fungal mat covering the surface (see photos). As well, when the cling wrap covering is removed a somewhat stronger smell is apparent. However, the smell is not unpleasant, being quite yeasty, somewhat like beer fermentation, but more earthy (and obviously without hop aroma). Directly smelling the spoon used to stir the brine brings out again the fungal smells, but also a sour smell – probably lactic acid bacteria. Haven’t had the courage to taste it yet though!

* In this case ‘canucklehead‘ was a bit vague about the amount and strength of the brine. At first he suggests: “the fermented disks are soaked in a brine that contains 8 oz of salt” and later “start out with 4lbs of water with 4 oz of salt”. That works out to about a 6% salt solution, by weight. I checked the label of my ‘naturally brewed’ Kikkoman soy sauce, and the salt concentration is about 7% by weight. So that seemed to be a pretty close match.

I also came across (have lost the link) a Google book about food safety in food processing . They talk about brining and different strengths and uses of brining. They said the minimum safe concentration of salt is about 10%; however later when discussing fermentation (of sauerkraut or pickles) they suggest concentrations of around 8% in order to allow the lactobacillus to thrive. This makes sense, as above 10% the fermenting organisms themselves are inhibited.

Canucklehead’s 4 lbs of water is about 2 liters, so I may be making a more dilute soy sauce (i.e. more brine per soy), but he says initially that his brine contains 8 oz of salt, which means that he would have needed about 4 liters of water. In that case, my soy sauce would be more concentrated. As with brine strength, I have gone with a middle estimate.

Subsequently on the eGullet forum on which canucklehead has been posting, “inigoaguirre” posted a link to his blog (unfortunately for me, in Spanish) showing some pictures of his soy experiment. As well, he states that:

the brine should have around 25% salt (you should heat at least a part of the water in order to dissolve the salt otherwise you would end up with all the crystals in the bottom). Kikkoman uses for their classic soyzu 23% salt; you can also find soy sauce with low salt content, but the proportion should still be quite high”

Not sure about this – on one hand, it looks like his soy sauce fermentation has succeeded (see his blog). Salt concentrations of 25% or so would definitely need boiling water to create the solution. However this concentration is well above canucklehead’s suggestion, and does not correspond to what my Kikkoman soy sauce (not low-sodium) bottle’s label states (you can calculate it yourself: per 15 mL serving there is 920 g sodium). What’s going on?

One idea is that Inigo and I are calculating salt concentrations differently (I’m fairly seat-of-my-pants on this). Although his statement about heating the water suggests that his salt concentration is indeed higher than mine (which just required a bit of stirring to dissolve). Also, the Kikkoman label deals with sodium, not salt…so the chloride part of salt is not included. As I am too lazy to revisit my high-school chemistry on molar weights, I have not bothered to figure out how much this affects my salt concentration calculations. My guess is not enough to bring my figure up to 25% though – chlorine is much smaller than sodium, and even if they were the same size, it would double the salt concentration to around 14%, still far from 25%.

Another hypothesis is that Inigo’s fermentation may not be via active bacterial/yeast culture. Rather, leftover enzymes (from the molds on the soy patties) that are not denatured in the saline environment may be causing the soy sauce to ferment. As well, if these enzymes produce acids, or if the mold produced acids in the soy patties, and Inigo has placed his fermentation jar out in the hot Spanish sun, he may be creating low-level acid hydrolysis reactions. Acid hydrolysis is how a lot of cheap ‘soy sauce’ is produced – although under industrial conditions using heavy duty acids and high heat and pressure. This is pure conjecture!!!

** Canucklehead says:

Large containers sitting out in the sun (under plexiglass). I actually don’t understand why this needs to be done – but my uncle says that my grandmother would always let the sun cook out the water – sometimes for a whole month. Perhaps this was a way to remove impurities – when tap water was not so safe”

I don’t really agree with his theory – based on what I have read about the manufacture of soy sauce, it is more likely that this practice was to warm up the fermentation, speeding it up, and creating more intense flavours. In Japan, before WW2, soy sauce was usually brewed during spring or fall specifically to achieve a mellower flavour from cool temperature fermentation. This also corresponds to beer brewing – fermenting at higher temperatures creates a lot of extra flavours that are not usually desirable in beer.

As this soy sauce recipe appears to be of Chinese origin, I have put my fermentation bucket in a warm spot in a very sunny west facing window.

Canucklehead goes on to discuss something I have read fairly frequently elsewhere on soy sauce fermentation:

I mentioned that they looked awfully pale to make a dark soy sauce – but he said that the brew will darken as it sits in the sun. “Just like how people get tanned.” Huh? I don’t understand how it can get darker – the brine is very salty – so I assumed that there would be no further fungal growth – but how can it get darker?”

Based on what I have read of Japanese soy sauce manufacture they ferment and age their soy sauce in the dark, and their soy sauce turns quite dark without exposure to the sun. The soy sauce is made dark likely by using roasted wheat, by pigments from the molds, by reactions during fermentation, and perhaps due to oxidation (like how an apple’s flesh turns brown with exposure to the air). On the other hand, it really may be that the microorganisms ‘get tanned’ somewhat to protect themselves from UV radiation by producing some sort of pigments.

And just to clarify (“I assumed that there would be no further fungal growth“), there is definitely active growth by microorganisms in the brine – from what I have read this includes most of the organisms involved in brewing beer: yeasts (kloeckera, saccharomyces, brettanomyces and probably others), and bacteria (enterobacteria, pediococcus, lactobacillus, maybe the clostridium and probably others). I doubt the molds themselves are able to grow so canucklehead is partly right – they are likely inhibited by the anaerobic and saline environment of the brine. So I believe their primary purpose is to pre-digest the soy beans and provide extra enzymes for the fermentation. They are themselves probably consumed by the fermentation yeasts and bacteria.

Soy Sauce Part 2: Dry Soy Chunks

Filed under: Soy Sauce — iwouldntlivethere @ 2:10 pm
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Step 7: Lay out moldy soy patties and allow to dry (outside in the sun if possible)

Step 8: When the outside of the soy patties had dried, I broke them into quarters to speed the drying process.

Here are what my dry soy ‘chunks’ looked like.

Note that they have turned a dark brown colour.

However a few of the thicker pieces were not quite as dark in the middle (see the close-up):

April 21, 2008

Soy Sauce Part 1: Moldy Soy Patties

Filed under: Soy Sauce — iwouldntlivethere @ 10:30 pm
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As per the instructions given by ‘canucklehead’ on eGullet’s forum, here is how I have made soy sauce at home:

Step 1: Soak 500 g dry soy beans overnight

Step 2: Boil soy beans until soft and crumbly

Step 3: Coarsley chop in food processor and mix with 300 g (whole wheat in my case) flour. I used whole wheat as it is less processed than white flour, meaning it likely has a greater diversity of microorganisms surviving in it.

Step 4: Form bean/flour mix into a loaf and slice into patties about 1 cm in thickness

Step 5: Lay out ‘soy patties’, cover with damp paper towels, and loosely wrap in cling wrap.

Step 6: Monitor patties, dampening towels as needed. Let sit for 5 – 10 days, until well covered by mold. In my case, the patties did not appear to be doing much for several days, but began to smell like my salt-risen bread starter (Clostridium bacteria). Then over two days the patties became completely covered in various molds:

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