Ask Mr. Wizard

How do I stop enzymes?


Kevin Huddleston • Milton, Wisconsin asks,

I brewed a Belgian clone with an OG of 1.091. Not knowing Laaglander Extra Light DME had such a high percentage of unfermentables, the wort got down to 1.042 and stopped completely. Adding fresh yeast, keeping the temperatures right and rousing the yeast regularly did nothing, of course, since the problem was the high percentage of starches in the wort. I didn’t want to bottle at 1.042 so I dissolved one teaspoon of amylase enzyme (and three teaspoons of yeast nutrient) into about 3?4 cup of boiled and cooled-to-lukewarm water and dumped it into the carboy. Within 24 hours, activity and bubbling started back up and a bubble was escaping the airlock every ten seconds or less, so the enzyme must have been doing its work despite being added at fermentation temperatures instead of mashing temperatures. Is there any way to stop the enzymatic activity when the gravity gets down to a reasonable level? Or will it just keep going until all the starches are broken down? I really don’t want to turn this batch into Belgian rocket fuel! Have I created a monster?


  I am not sure you have created a monster but you may have a runaway train on your hands! There are only two ways to stop an enzymatic reaction. You can
Response by Ashton Lewis.