My Brewing problem

[Bryan.]

Hi everyone,

I’m having trouble with a sour taste in my latest batch. It was noticeable during bottling and persists even after conditioning.

Details:
New Grain Batch: Used new grains.
Temperature Fluctuations: Fermentation temperature wasn’t stable.
Could this be due to an infection or something else? Any advice on troubleshooting or preventing this issue would be appreciated!

 

[The Baron]

You need to give us the recipe method and yeast used oh and the temp fluctuation.
Initially sounds like a Lactobacillus or could be a PH issue too but full info will get better answers

 

[Stu's Brews]

If it is sour, and not intentionally, then it's almost certainly going to be due to an infection. Most likely some wild yeast or bacteria has been introduced to the wort on the cold-side.

Other less likely causes (things that would reduce the pH of the final beer and give it a sour taste);

• Use of too much lactic acid (or similar) when adjusting your water.
• Use of too much acidulated malt.
• Prolonged acid rest during the mash (~38degC).
• Use of malt that has been allowed to get wet, and thus infected, prior to be brewing.
• Use of a high quantity of roasted malts.

 

[JockyBrewer]

If it is sour, and not intentionally, then it's almost certainly going to be due to an infection. Most likely some wild yeast or bacteria has been introduced to the wort on the cold-side.

Other less likely causes (things that would reduce the pH of the final beer and give it a sour taste);

• Use of too much lactic acid (or similar) when adjusting your water.
• Use of too much acidulated malt.
• Prolonged acid rest during the mash (~38degC).
• Use of malt that has been allowed to get wet, and thus infected, prior to be brewing.
• Use of a high quantity of roasted malts.

The others are all good points, although they'll generally add a slight tartness rather than sourness. I'll add that there's also a few yeasts that drop the pH more than others, such as the main hefeweizen yeast WLP300 that do the same.

Most likely is a lacto infection, and that usually happens between the boil and the yeast getting active in fermentation, and occurs due to:

- Poor sanitation of fermenter and transfer equipment. Particularly if the fermenter has been exposed to grain dust in the air which is covered in lactobacillus.

- Pitching insufficient yeast resulting in a long lag time that allows the bacteria to take hold.

- The wort being quite warm (high 20s/low 30s), giving bacteria an ideal environment to replicate in.