The on-going soy sauce controversy…

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.

Yogurt making

Well, after this post on my home made yogurt, I’m running out of fermentables to write up, I think only bread remains undocumented. Yogurt making is actually one of the primary reasons I started this blog, as it was Jen B.’s interest in it that prompted all this. However, I only make yogurt once a month at most so it has taken a while to be able to take pictures of the process (and on the day I made it one camera was out of power, and the other with my wife, so I had to use an actual film camera with a few pictures left, then get them developed - can you notice difference? The last 3 pictures were taken with a digital camera) . I usually make five tubs of 750 ml in each batch, which lasts us for over a month often.

This longevity is, I believe, the original reason for making yogurt - as a way to preserve dairy products. Only one batch (when I discovered that my electronic thermometer gives funny readings when immersed in water for long periods) had issues - a bit of mold growth on the sides of the last tub when I opened it (but the yogurt itself was OK - at least, nothing happened to me after eating it). The reason for the mold was that because my thermometer was not working properly, I was not holding the yogurt at high enough temperatures, so it did not acidify enough, which in turn made it more susceptible to mold infections - but only marginally so.

So, the theory behind yogurt is to ferment milk using a lactobacillus/thermobacillus culture to acidify it to help preserve it, and (a bit less clear on this part) to make it more easily digestible by adult humans. Initially the milk should be scalded - briefly brought up to at least 95 degrees . From what I understand, this is to modify the milk protein (makes the yogurt thicker and taste better), and probably kills off most competing bacteria. To properly and quickly ferment, the milk must then be held at temperatures between 40 and 50 degrees for several hours.

In practice, this is how I do it:

Here I have assembled the ingredients (milk, and store-bough active culture yogurt) and the scalding pot and thermometer.

Here the thermometer shows 95 degrees - the milk has finished scalding. I use only medium heat to do this as I find that it means less burned-on milk at the bottom of the pot, and it is easier to prevent boil-overs.

After scalding the milk, I cool it down to about 55 degrees (here the thermometer shows 53) in a cold water bath in my sink. This takes about 5 minutes - if I stir both milk and water.

Here I have divvied up the starter culture between the five tubs I will be using (I used Astro's Balkan style yogurt this time - this was the best culture I have used so far, as it made a very thick and proper yogurt). Although this means only 150 ml of yogurt starter per tub, I have not had any trouble starting fermentation.

Here is how I ferment the yogurt. I place all 5 tubs in this picnic cooler, and immerse them in the hottest tap water I can get - usually around 54 or 55 degrees. I then monitor the temperature, and when it falls to 40 degrees (usually takes at least 90 minutes) I empty the water and refill it with hot tap water again. I usually do this 3 times.

Here's a comparison of temperature readings from my electronic thermometer and my brewing thermometer. The electronic one shows 53 degrees, while the brewing thermometer shows only 49 degrees. Not sure why or which one is right, but I trust the brewing thermometer more!

This is what yogurt making looks like for most of the time it takes to do.

The finished product! After about 4.5 hours, the fermentation has acidified the milk, and it has turned into a nice thick yogurt. Notice how rigid it has become - even when tilted to a 45 degree angle. To me, it tastes pretty much the same as yogurt I buy (others describing their own yogurt say it tastes 'creamier'; the only time I found this to be true was the time it did not acidify enough because my thermometer mislead me, and it did not ferment properly). I have also read elsewhere that you should mix in dehydrated milk powder to achieve the thickness of commercial yogurts (or that commercial dairies add artificial thickeners to achieve their thickness). I don't really agree - my yogurt has always been as thick as the stuff I buy, so no need to add any milk powder, and it makes me doubt that artificial thickeners are neccessary even on a commercial scale - lactic acid works fine. What probably is happening is that people making their yogurt at home may not be keeping it warm long enough to produce sufficient acid, or they are not keeping the temperature high enough.