I can make a nice microfoam with both brands of soy milk I use (Earth Balance unsweetened and Organic Valley unsweetened) but when I pour to make latte art, it is too thick and floats, creating poorly defined shapes at best.
I heard about a Pacific brand soy milk made specifically for making lattes called Barista Series, Soy Blenders. I looked it up on amazon.com and start reading people’s comments. People seemed to really like it and pointed out that it was able to withstand higher temperatures than other soy milk. I found the information and photo below on the pacific foods web site and they too claim that it can withstand high temperatures.
Pacific Barista Series™ Original Soy Beverage (Formerly Plain Soy Blenders)
Specially formulated to withstand high temperatures and deliver consistently smooth, velvety microfoam. It performs as well as (or even better than) dairy – perfect for latte art.
I did further research on the subject of soy milk curdling at high temperatures. There was a a difference of opinion on the cause. Some said that it was due to excessive heat while others claimed that it was caused by acidity. I researched further and found this study that showed that it was acid alone that caused curdling un-influenced by heat!
|On Barista Exchange.com I found this useful comment by Jacoby Steele.||Soy doesn’t have the same consistency as milk, or the nutritional make up- so it really shouldn’t be treated exactly like cow’s milk… I’ve had success with keeping the tip of the wand to a 45* angle like you’d do for a capp, and barely submerge the tip. You want to have constant texturing until about 100* and then barely submerge it to keep everything moving. Soy foam has a bad habit of separating quickly if you don’t let it mix (or swirl) under the wand as long as possible. and don’t steam it over 130*. I’m lactose intolerant and i can pour decent latte art with the technique i just described without curdling.|
|Here is another comment on the same page that might be helpful.||Reply by Chris Holden on April 18, 2012 at 9:35am So if anyone is interested in the science, by adding soymilk to hot coffee you are basically following the recipe for making tofu! Heat + coagulant + soymilk = tofu, though usually a salt such as magnesium chloride (nigari) is used as a coagulant rather than an acid. Lemon juice can actually be used and although coffee is not sufficiently acidic to make usable tofu, it will make a mess of your drink. Typically temperatures of around 170F+ are used for tofu production, though again, anything over 120F coupled with an acid could be enough to spoil your drink. Some soy creamers may contain a stabilizer to prevent this and the variations people experience are usually down to additives of some kind in their soymilk, though I can’t recommend one in particular. Otherwise you are fighting the laws of chemistry I’m afraid! (I do actually make my own tofu regularly for Japanese cuisine and find the art & science of it almost as interesting as that of coffee!)|