In the bean digestion
thread I made the following post about enzymatic action in regards to the complex carbohydrate oligosaccharide.
The enzyme needed to break down beans is alpha-glactosidase. Cantelope, green coffee beans, and yeasts produce it in large quantities. Note that cooking will destroy this enzyme. However in the case of fermentation with yeast, the enzyme will break down the oligosaccharides during fermentation, and cooking it afterwards to kill the yeast is perfectly admissible. The mold Aspergillus oryzae produces a lot of different enzymes that work together to liberate simple sugars from oligosaccharides. This in combination with yeast is known in Korea to produce a potent wine from beans. If the beans are fermented with either yeast or the mold I mentioned above, you will have no gas from it.
To make wine from beans, you first have to break down oligosaccharide into simple sugars. In Korea, this is done by first cooking and mashing the beans and fermenting it with Aspergillus oryzae (commonly called koji). The enzymes produced by koji will break down the complex carbohydrates. If you ferment it too long it will taste like soy sauce. You can tell when it is ready by tasting it. It
should taste sweet. If it tastes beany or starchy it needs to ferment longer. If it tastes like miso or soy sauce it has gone too far. Once it tastes sweet, you have to stop the fermentation and suspend the simple sugars in
water. This is accomplished by transferring the fermented paste to a pot of water and boiling it for a while. You can use a hydrometer to test sugar levels. Then strain the liquid into a clean fermentation vessel and let it cool to room temp before pitching in a beer yeast. There will still be some starches in it and beer yeast is better able to consume them. Ferment until your airlock stops bubbling. You can stop here and bottle it, or you can distill it to make the Korean equivalent to moonshine.
Another permutation if you lack koji is to malt the beans. You want to soak the beans and then sprout them to the point that a tiny
root is visible, then dry in the
oven and grind into a coarse meal. After which you boil the meal and proceed from the straining step as written above. The flavor will be drastically different.