Turning Tofu to Liquid with Alkaline Solution

In this video the cook fries tofu then places it in an alkaline bath to turn the inside liquid. Think spherification but with a 300 year old technique.

Has anyone tried this, or know a starting pH to work from? I will use Cal Mexicana to make the alkaline bath.

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Brendan_Lee_56950

That's awesome. I'm trying to find the chinese name for the dish, i'm sure that will make it easier to search out. I'll have to ask my mom if she knows.

Jack_Mayer_85396

What a cool technique and a great looking dish!

Tim_Roth_78505

I'm (slowly) starting to look into this, and I'll definitely post if/when I have something more concrete. For the time being, the wikipedia page on soy protein suggests that many of the processes of extracting the proteins happen at a pH below 9. So in terms of testing, I might recommend starting there and maybe trying 8, 9, and 10 or something similar (8 or below probably shouldn't have an effect given that my tap water growing up was pretty close to that pH). I can't imagine that you'd want to go too much higher than that anyway for safety reasons, but at the same time this sort of extrapolation is based on the native soy proteins rather than coagulated mass of tofu.

Here's the wikipedia page: http://en.wikipedia.org/wiki/Soy_protein

Tim_Sutherland_52834

Thanks. I'll play this weekend and set up a few alkaline baths, drop some fried tofu in and see what happens.

Brendan_Lee_56950

Annoyingly, googling alkaline tofu pulls up all the fad diet shit

Tim_Sutherland_52834

So I grabbed my pH meter, extra firm tofu, Cal Mexicana, deep frier and played.

I made five baths:

Tap water pH 7.76
10g Cal Mecicana in 1,000g tap water, pH 12.39, thick layer of salt solids on bottom.
5g Cal Mexicana in 1,000g tap water, pH 12.28, thick layer of salt solids on bottom.
1.5g Cal Mexicana in 1,000g tap water, pH 12.12, layer of salt solids on bottom.
0.5g Cal Mexicana in 1,000g tap water, pH 11.59, very, very slight salt solids on bottom.

The water from the tap was ~31°C for all baths at time of filling.

Extra firm tofu was pressed, cut into equal size chunks (via eyeball) and fried in ~185°C oil until GBD.

After cooling for ~1 minute, 3 pieces each were dropped into a tap water bath, 12.39 pH bath and 11.59 pH bath, and left for 30 minutes turning every 10 minutes. Via touch after 30 minutes all were firm and so left for another 40 minutes turning every 10 minutes.

Each batch was then dropped into a boiling pot of water for 1 minute (starting with the lowest pH) then placed in a ~30°C holding bath.

The fried only piece (no water bath) was nice with firm tofu - no liquid was visible.

All the tofu looked the same when cut. No real liquid was visible when cut. The tofu did feel softer the higher the pH. The mouth feel of the highest pH was much softer than the others for both my wife and I. There was no real difference between the water and the lower pH. There was a slight difference between only fried and tap water, with the tap water been softer.

Researching this recipe is difficult, as I don't have the Chinese name for the dish; the exact type of tofu is not stated; the pH of the alkaline bath is not known; searching "alkaline + tofu" produces pages of fad diet results.

I need to play with different pH baths and types of plain tofu to see which, if any, turn solid tofu to a liquid, and then try the frying step.

Brendan_Lee_56950

I'm still on the lookout for the name. I've asked an author of a tofu book and she had never heard of it before unfortunately.

Jack_Mayer_85396

@Tim, thanks for undertaking the test ... If I can assist, let me know.

Tim_Roth_78505

Here's a resource I pulled up from a google search that mentions the following: "The reason that people do not precipitate tofu curds at the relatively acidic isoelectric point (pH 4.2, the point of minimum nitrogen and protein solubility) and then neutralize it is that the proteins tend to redissolve as the pH moves back up to neutral." This sounds similar to what you're trying to do in liquefying the fried tofu interior, so I think your idea of comparing the different types of plain tofu is spot-on. It might be worth it to see if you can't find a silken or soft tofu that lists acid as a primary ingredient (although it doesn't sound like acid-coagulated tofu is that common to begin with, so I'm not sure that it's a requirement). I'll keep digging for more details.

http://books.google.com/books?id=sYUq27wYcKMC&pg=PA126&lpg=PA126&dq=acid-coagulated+tofu&source=bl&ots=P-kcVl8cjx&sig=wmOu3daaQxVAJQ-EyTYBIwWDdIo&hl=en&sa=X&ei=bgeEU7KWPOPfsATyloHIAg&ved=0CE4Q6AEwAw#v=onepage&q=acid-coagulated tofu&f=false

Anthony_DeGeorge_1721870

Hello from the future. I'm trying to find more information on this topic. Did you find anything further? Thanks.

Anthony_DeGeorge_1721870

Hello from the future. I'm trying to find more information on this topic. Did you find anything further? Thanks.