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  • Writer's picturePaige Latham Didora

the biggest mistakes new breweries make, part two

For part one, click here.

First in the Biggest Mistakes series was a look at the problem of new breweries serving premature beer to paying customers. Turns out I am not the only one who has experienced this, and it’s a frustrating reality. But you, dear readers, pushed me further on the issue – “what about plain, garden-variety, BAD beer?”

You asked. Fair enough. My previous series outline will be scrapped to appease the masses.

The reality is that there are shortages in this industry – areas that have been stretched very thin due to rapid growth. I am not talking about the looming hop scarcity or water problems that brewing forecasters often predict with a tone of doom and gloom. I mean knowledge, experience, and the often-overlooked ability to edit oneself.

Off Flavors Guide

Bad beer is not beer that you don’t like. A beer isn’t necessarily bad because it doesn’t fit its name or style category. Bad beer is beer that contains off-flavors, evident of process issues. There is a spectrum of problematic beer, from a bit off to downright undrinkable. Depending on one’s palate, certain levels of “off” are acceptable. For those who want to live in ignorant bliss and enjoy most of what goes in thier mouths, I certainly won’t argue. However, for a bit of palate honing, read on for Alcohol by Volume’s Guide to Off Flavors, or what I like to call “how to taste what you shouldn’t be tasting”.

Off-flavors, as they are so dubbed in the industry, are unpleasant flavors in a batch of beer. These tricky little jerks arise from a number of sources, but mainly are due to a process or recipe issue – too high a percentage of roasted malt, improper sanitation – or a fermentation problem – pushing yeast too far, fermenting at too warm a temp. Off-flavors are acceptable or even desired in certain amounts in particular styles of beer – phenols in hefeweizen, DMS in cream ale. It is always good to consult the BJCP style guideline regarding what is appropriate. However, they make themselves known when they are out of place.

The most common off flavors are (FYI some are nouns, such as specific chemicals, while others are descriptors) Acetaldehyde, Acidic, Alcoholic/Hot, Astringent, Cidery, Diacetyl, Dimethyl Sulfide (DMS), Estery, Grassy, Medicinal, Metallic, Moldy/Musty, Oxidized, Phenolic, Skunky, Soapy, Solvent, Sulfuric, Sweet/Wort, Yeasty

The highlighted ones are those that have been most prevalent in my experience.


One at a time, shall we? Since the holidays have just concluded, let’s talk about butter in beer before we all go on diets and forget what butter tastes like.

Diacetyl is the chemical that is responsible for making beer taste like butter, or, more accurately, fake butter. Diacetyl smells and tastes like the orange film on the bottom of the microwave popcorn bag. It is not the butter, nuttiness, or woodiness of chardonnay, it is offensive butter.

How does this happen? Diacetyl is the result of the fermentation process but can also arise from bacterial infection. Normal fermentation results in diacetyl early on, but towards the end of the process, it is converted into something chemically different.

Considering that bit of chemistry, beer that isn’t kickstarted into a strong fermentation is as risk for diacetyl in the final product. Thus anything less than robust yeast can be the issue, as can lack of oxygen in the wort. The opposite issues – highly flocculating yeast or over-oxygenation – can also be a problem, though, because fermentation will occur so quickly that the yeast do not have time to reconfigure diacetyl.

“One of the key elements of maturation is diacetyl reduction. Not only do yeast produce the precursor to diacetyl, they also consume the diacetyl that is produced and enzymatically reduce it.” [BYO] Steps to take to avoid DMS include a process called diacetyl rest, particularly important for lagers due to their cold fermentation. It involves raising the fermentation temperature by a little over ten degrees for about two days.

Are off-flavors only found at new breweries? Certainly not. But for a number of reasons, including in many cases lack of experience, new breweries can be an off-flavors mine field (or educational forum of sorts).

Off-flavors will be visited regularly on ABV, so long as there continues to be a slew of bad beer out there. Armed with this knowledge, consider whether you encounter any buttery beer in the coming weeks. And follow along the Biggest Mistakes series for further discussion.

The only butter that should be found in beer is in Harry Potter. Cheers to better beer!

Further Reading:

Mosher, Randy. (2009). Tasting Beer. New York: Storey Publishing

#BadBeer #craftbeer #Minnesota #offflavors #diacetylrest #beer #infection #Newbreweries #brewing #diacetyl #BiggestMistakes #homebrewing

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