[rookiet]

Hi everyone,

I've been making tofu for a while, starting from home-made soy milk from dried beans.
Originally I was using gypsum/calcium sulfate which is the coagulant for the traditional tofu. Recently moved up to GDL which is an absolute game changer for me.

I usually use 1.5% GDL relative to dried bean weight, and so far, I have been making my soy milk with a 1:5.5 bean (dry weight) to water ratio.
So for instance, when making 4000mL soy milk, I will use 730g soy milk (dry weight), and coagulate with 11g of GDL.
The tofu that comes out produces a slight sour note, as GDL is an acid, and thought that was just an unavoidable trade-off.

That was until a new container (that I make the tofu fa in) arrived and I was dying to test it out in the laziest way possible - I bought soy milk.
And because I have no way of knowing the bean concentration, I simply used the same ratio as though it were my home-made soymilk. Ergo, I bought a 2000mL bottle, and coagulated it with 5.5g GDL. To my shock and horror, there was absolutely no sour taste - it was completely neutral!

The soy milk was "Fortune" brand (unsure if this is popular globally), and the protein concentration per 100mL is usually around the 2.8g to 3.1g mark. Not sure how the math works to determine their bean concentration. There's the obvious loss when grinding, mulching and filtering the beans that would make it hard to accurately calculate what my soy milk is like.

Anyway, what I'm confused about is that I would have thought the sourness/acidity observed by the consumer would be determined by the acid material (i.e. the GDL) relative to the volume of whatever it is (in this case, the tofu/soymilk). So when I have the exact same ration of GDL to soy milk, it's surprising that they taste different.
So all else equal, I suppose that the store bought milk and my milk has different concentrations. However which direction should I travel towards? Does the store bought stuff have more protein, or less protein (the texture came out quite identical, but maybe slightly firmer)? Anyone have experience with this?

Cheers all!
- Rook

 

[Sandesh]

I am by no means a tofuologist, but I like a little sour taste with most tofu preparations.

 

[brianshaw]

What is GDL?

 

[rookiet]

GDL is Glucono delta lactone. The common coagulant used in the production of Silken Tofu. It differs from Gypsum (i.e. calcium sulfate) in that it gives a silkier, more slippery and elastic texture compared to traditional tofu coagulated by calcium sulfate. The latter of which gives off a more gritty, coarser and more brittle and grainier texture.

What the tofu made with GDL offers (improved texture), it generally loses out to gypsum in taste (it's sour). If done correctly (which obviously is not my case), a GOOD tofu (at least, imho) should be completely neutral in flavour, besides the natural (very mildly) sweetness from the soybeans.

 

[brianshaw]

Ahhhh, thanks.

I understand the quest for neutral taste in silken tofu, especially when used as a dessert component.

 

[chrislehrer]

I have never made tofu, but I've been in a fair number of tofu-making shops in Japan, and eaten way too much tofu and related products in Kyoto.

The first thing that leaps to mind for me is the dried soybeans. In my experience using them as an ingredient in various dishes, they vary considerably more than do, say, pinto beans. A lot of the packages seem also to sit on shelves for long periods of time, and may also be transported in sketchy temperature environments. In short, I often find that "new" soybeans "fresh" out of a sealed plastic bag smell slightly musty, and that there is a lot of variation in that smell.

The people who make soy milk don't have this problem, because obviously they can get their product at source quite directly.

So my suspicion is that your beans are producing the hint of sourness, not the coagulant. I suggest trying your GDL recipe with several different batches of unopened beans from different brands and retailers, if at all possible, and see whether you get flavor variation.

 

[rookiet]

I have never made tofu, but I've been in a fair number of tofu-making shops in Japan, and eaten way too much tofu and related products in Kyoto.

The first thing that leaps to mind for me is the dried soybeans. In my experience using them as an ingredient in various dishes, they vary considerably more than do, say, pinto beans. A lot of the packages seem also to sit on shelves for long periods of time, and may also be transported in sketchy temperature environments. In short, I often find that "new" soybeans "fresh" out of a sealed plastic bag smell slightly musty, and that there is a lot of variation in that smell.

The people who make soy milk don't have this problem, because obviously they can get their product at source quite directly.

So my suspicion is that your beans are producing the hint of sourness, not the coagulant. I suggest trying your GDL recipe with several different batches of unopened beans from different brands and retailers, if at all possible, and see whether you get flavor variation.

Hi Chris,

I think you're onto something there. Yesterday I tried increasing the bean concentration to 1:5. I made 2000mL soymilk with 400g beans, whilst even reducing the GDL to 5g. The sourness is still there, but noticeably reduced due to less GDL. However it wasn't "eliminated" like when making it with the store bought soymilk. The firmness took a hit - it didn't feel "fully" set, almost as though there was not enough coagulant to work with the added protein. Still kept in shape but there's a bit of fluidity to it that shouldn't exist.

So, long story short, manipulating the GDL to protein ratio isn't the way to go - it's still a compromise between set quality and acidity. And also proved that it wasn't because there was more protein content in the store bought stuff, otherwise the store bought stuff wouldn't have set so nicely. Although it's a completely plain, unsweetened soy milk, I wonder if they snuck in anything else that offset the taste. Otherwise, like you said, they probably made the product from fresh beans.

I'll eventually try your suggestion, but for now... I still have 3kg of dried beans to go through LOL