Causes Of Sour Taste In Beer

It’s one thing to enjoy a Belgian Lambic and another to spit out a sour Pale ale and hope you don’t fling your glass across the room in disgust… Regarless, the things that sour your beer are pretty much the same, only in some beer styles, brewers purposely add these souring agents, while other styles, brewers just plain suck at brewing… just kidding, they are learning…

All right, so here it goes… Lactic acid is probably one of the most common souring agents found in beer…. and how exactly did it get there?

Well thank our good ole bugs known as Lactobacillus… you know the stuff they put in some yogurts that’s supposed to help your body by turning sugars into lactic acid which then inhibits the growth of other harmful bacteria in your guts… that’s the stuff…

In yogurt, ehhhh, I guess it’s all right… in beer?… it depends on whether you are into Belgian Lambics or Berliner Weisse beers…

The next bug that is commonly known to get into beers without the brewer’s consent is the Acetobacter… Aceto meaning acetic and Bacter meaning bacteria, basically tells you that this bacteria likes to produce acetic acid… it’s a vinegar like acid so it can taste kind of cidery… these two bacteria are more than likely the causes of sour taste in Beer, when a brewer isn’t exactly looking for a sour beer…

Acetobacter needs oxygen and it’s an aerobe, which means it’s likely to get into your beer if you are allowing air and oxygen in during transfers… it usually means you need to pay more attention to how you clean your home brew equipment and sanitation.

Now, there is another bacteria which is actually used to produce the same lactic acid that lactobacillus produces… this bacteria is known as Pediococcus… unlike lactobacillus, however, this bacteria also produces a buttery flavor when eating sugar… this is a common off-flavor although desired in other styles, but not coming from pediococcus…

In order to combat this buttery flavor, brewers use a wild yeast which they’ve kindly named Brett… full name is actually Brettanomyces, but Brett is easier to say (and remember)…

Now if you don’t already know, regular brewer’s yeast eat the sugars in your wort and turn them into alcohol… but they don’t eat all sugars, only some types…

Well, good ole Brett is a sugar munching little creature that will eat all types of sugar… I mean this guy is to be feared in breweries because they can really cause some damage if not controlled… so brewer’s that use this wild yeast use only enough to combat the buttery flavors put out by Pediococcus…

Pediococcus and Lactobacillus are usually used to sour along with Brett to battle the off-flavors… You can find both the yeast strain and bacteria at your local home brew supply store…

Well, this pretty much does it… if you are planning on giving your beer a sour taste this how… if you weren’t planning on it, this is why… don’t forget to clean and sanitize next time…

3 Comments

  • Bobby Rock

    Reply Reply November 2, 2010

    Hm interesting, thanks for the information will def help me next time i brew beer.

  • Tommy

    Reply Reply December 27, 2010

    Also NEVER use powdered sugar as your priming sugar for bottling. It causes a very bad taste in your beer. I did this due to some bad info that I got on a website and ruined two batches befor I figured out what was causeing the bad taste.

    • Jorge

      Reply Reply December 27, 2010

      Hmmm… interesting… I’ve never heard of anyone try to use powdered sugar for priming. I guess confectioner’s sugar has some additives like cornstarch, wheat flour or calcium phosphate, and that may be what causes a bad taste in beer.

      Thanks for letting us know…

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