I got the opposite of whet you meant at first, did you mean ‘to prevent it from leavening at all’? I found this in wiki and only then did I got it:

Dough is considered to begin the leavening process 18 minutes from the time it gets wet; sooner if eggs, fruit juice, or milk is added to the dough. The entire process of making matzah takes only a few minutes in efficient modern matzah bakeries.