What is Diacetyl in Your Beer and How to Prevent & Fix It?

Have you ever gone to taste your beer and noticed a slight buttered popcorn taste or smell to it? Well, that would be the unfortunate chemical compound called Diacetyl. In this episode, we will take how to prevent it and fix it if that happens.

Now how diacetyl gets into your beer is a little complicated so we will break it down as simply as we can. But there are two primary ways you can get this in your beer. This flavor is usually very noticeable when you are getting ready to bottle your beer, so there are a few things you can try to do to help prevent this.

Either through slow or inefficient expression and intracellular reduction of naturally occurring diacetyl precursors or by a bacterial infection

Let's break down the second way first as that is more simple. The best way to prevent that is just to have good sanitization since it is a bacterial infection. So if you get diacetyl in your beer make sure to give all of your equipment a thorough cleaning with a brewery cleanser, not a sanitizer, but something that will clean your equipment. We use the Craftmesiter Oxygen Brewery Wash which works really well.

The second reason is a little more complicated. There is a precursor to Diacetyl and that is acetolactate. If you do not give it the time or proper conditions to be absorbed in the beer, you can do a few things.

If you bottle your beer and get that buttered popcorn taste or smell, you should let your beer fermenter for 2 more days but raise the brewing temperature by 2-3 degrees. This can help dramatically reduce the amount of this compound in your beer.

So to make sure you are preventing this, you want to make sure you keep your brewing equipment clean, make sure you have excellent sanitation, and make sure you are brewing in the proper temperature range suggested in your brewing instructions.

If you have this taste in your bottles, you can let your beers condition at room temperature for a few weeks, which might help the flavors.

To recap just make sure you are sanitizing and holding your proper brewing temp and you should be good!