Just racked an oatmeal stout to secondary after 3 weeks in primary. Smelled like bananas A LOT. Starting gravity was high as expected so I pitched 2 rehydrated packs of safale 04. Will this fade with time in secondary?
That is odd as 04 is clean typically. Banana is usually there to stay. Sounds yummy to me
I agree with @squeegeethree 04 ferments clean. What temp was fermentation?
Me dont use it so much. But wrong. Temp gives of flav. Us 4 my back up yeast. If i use it. Got to keep my fermenting temp under control
Isoamyl acetate production is what causes the Banana smell and taste. Some strains of yeast produce it like hefeweizen yeast. Other strains can produce it because of high fermentation temperatures or Stressed yeast, under pitching and poor aeration. High amounts of zinc in your water or wort can aid in the production of it.
65 to 68ish. I’ve never had a problem with fermentation before so I’m just trying to get to the bottom of it.
Looking back at my notes, took about a day and a half for fermentation to kick off. When I use safale 05 I usually see it kick off in under 12 hours. Is that a normal timetable for the 04?
On the bright side it does tend to fade with age. As for getting to the bottom of the cause. Isoamyl acetate production is from yeast. Since your temperature was in range you can rule that out. Stressed yeast is common cause and you said you rehydrated your yeast. What temperature did you rehydrate your yeast? Also was the yeast out dated or old? I will be honest i never rehydrate my yeast at home or at the brewery. My practice is once transfer has started and temperature is with in range i pitch the yeast in the fermenter and let my wort rehydrate it and mix. Then i aerate with oxygen. If you dont have oxygen shaking the fermenter allows for a small amount to get in. Not as well but is a common practice among us homebrewers. Next is zinc in your water or wort. You can manipulate your yeast to produce Isoamyl acetate with high amounts of zinc. So testing you water and knowing your water profile will help you with future brews.
I rehydrate with room temperature water (boiled first) admittedly I’m not sure about the age of the yeast but my local homebrew shop has never let me down. I added some cocoa nibs to secondary so hopefully that and some time will help this batch. Since that batch I’ve purchased an erlenmeyer flask and stir plate so I don’t plan on using the dry stuff anymore. Thinking back, I usually cool the wort to 80 degrees before transferring to primary fermentation and shaking the crap out of it, maybe I need to cool the wort even more?
Yes. I would try to cool to fermentation temp, or even a bit cooler. That could be it…