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 predominent 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 infection during cooling starter
WoodenPlastic spoon used to circulate wort when cooling with wort chiller
- Aerial infection 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?
After my IPA (in which I also used a wooden spoon to cool the wort, but in which there was no infection), I stopped using my wooden spoon, and now use a plastic one. With the plastic spoon, I brewed a Stout, that did not have any infection, but the subsequent batch (a Saison) was infected, and I used no wooden this time.
Also, normally I turn off the oven fan when cooling my wort (to reduce aerial infection risks), but sometimes I forget.