Consecutive (lacto?) contamination with different fermenters

Question

My two last batches got a sour/white wine taste to them (prior to bottling).

The first one was a Hefeweizen fermented in my bucket. The taste was present from day 4 up to bottling a month later. In my memory, there was no film on the beer in the fermenter.

The second one was a Brett Saison (WL Farmhouse Blend) fermented in my glass carboy. I tasted it yesterday after 3 weeks of fermentation and it had the same taste. There are little white round things on top the beer in the fermenter, but it's maybe just the Brett in the American Farmhouse Blend.

The taste is predominant and hides every other tastes.

Since I didn't use the same fermenter, that's not the problem.

My understanding is that the culprit must be some equipment/process after flame-out (and/or starter equipment). Also, since I got the taste 4 days into the fermentation of my Hefeweizen, it's not any racking equipment's fault.

Pretty much leaves :

• Starter container (glass jar + aluminium foil for covering)
• Wooden spoon used to circulate starter when cooling with ice bath
• Aerial contamination during cooling starter
• Wooden spoon used to circulate wort when cooling with wort chiller
• Aerial contamination during cooling wort
• Strainer used to filter wort when pouring in fermenter
• Spray bottle used for spraying sanitizer

Obviously, I sanitize every piece of equipment (with a no rinse sanitizer, OXY-SAN I think).

Any clue what's the most likely suspect?

Answer 1

I'd put my money on the wooden spoon. Legend is that in days of yore, brewers used to stir the wort with a "magic stick". If they didn't, it wouldn't ferment. The reason was the yeast imbedded in the wood. I've always been told not to use wooden spoons post boil. That makes sense to me.

Answer 2

Another thing to consider along with the wooden spoon is if you grind your grains in the same room as you brew.

Lactobacillus comes from the grains and while grinding or even pouring out of the bag, tiny grain particles can float in the air for a while like dust. These small particles can then find their way into your cooled wort or fermentation vessel. The way to stop this is to always grind your grains in a different area from where you brew.

Answered by: The Gastrograph Team