Tag Archives: butterscotch

Diacetyl & My First All-Grain Batch

Things weren’t looking good for my first all-grain batch. I didn’t have a mash ton for a start. I’m not going to try and explain how much of a failure the 6-hour-long brew day was, and I’m not going to bore you all with the details about how I covered my kitchen in spent grain and sticky wort, but suffice to say things didn’t go to plan and I ended up with more beer on the floor than in the fermenter.

What I do want to talk about though, is the heavy butter taste that my beer has half way through fermentation. It tastes like butter popcorn and buttered bread – not a great taste in a 2% pale ale!

After some research online, I discovered that this buttery taste was caused by the chemical Diacetyl. According to Wikipedia, Diacetyl is a main flavour component in Butter. At low levels, diacetyl contributes a slipperiness to the feel of the alcoholic beverage in the mouth. As levels increase, it imparts a buttery or butterscotch flavor. Diacetyl is produced by the yeast as they turn the sugars into alcohol.
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