Does boiling water deactivate malt enzymes? Will mixing boiling water with malt flour deactivate the malt enzymes?
I’m trying to adapt a recipe for mämmi that involves mixing mixing a combination of malt+regular flour with boiling water in a 1:2 ratio (by weight) and need to understand whether the point is to stop the enzymes or to encourage their action.
Overall it is add 3 parts boiling water to 1 part malt, then 2 parts regular flour, off the heat. Mix and let sit.
Yes, heating to boiling temperature will destroy amylase.
Depending on the ratio, the goal of that recipe may be to destroy the enzymes, to gel the starch, or to help the enzymes be most effective. It’s not uncommon for particularly old and traditional recipes to use a combination of boiling water, ice-cold water, and room-temperature ingredients to reach a particular temperature, as the ratio of inputs will determine the final temperature pretty accurately without a need for a thermometer. If the water to malt/grain ratio is about 1:1 by mass, that would put the enzymes at their optimum temperature for converting starch to sugar. If it’s a lot more water than malt/grain (again, by mass) then the purpose is more likely to deactivate the enzymes and/or gel the starch.