Yeast create biomass with the access to oxygen, aerobic fermentation. Anaerobic fermentation produces alcohol and co2.
My understanding is that yeast do not respire in wort, regardless of the presence of oxygen, due to the Crabtree effect.
I did win the gold medal in weissbier at NHC this year (final round) with a hefe
Nice! Congratulations.
Thanks, appreciate it!
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Forgive me if you already did and I lost it somewhere in the last 9 pages but, to bring this back around to where the OP started: care to share your gold medal recipe?
I don’t have it on me at the moment, it’s in the Zymurgy medal issue.
Off the top of my head, It’s like:
Fairly soft water with 1g/gal cacl/strike water
50/48/2 wheat/pils/melanoidin
Couple grams of magnum 10 ibus or so.
Wlp380
Mash in at acid rest 10-15
Protein rest 10 or so.
Beta 45 mins or so.
I think I skipped an alpha rest if my memory serves me correctly.
In Zymurgy I called it an open/closed ferment.
pitch at 15c and open ferment at 15c (15+15 comes from the 30 degree rule or whatever they call it.) ferment 72 hours
Transfer to a keg with speise in it, keg condition 72 hrs at like 18c is the closed part
I let it build to a bout 2.8 bar or like 40 psi(whatever the bar equivalent is)
Crash, usually lager for 10-14 days, but for the comp with shipping and stuff I bottle it about 3 days after the crash. Usually for comps my hefe’s smell like malt, wheat, light clove, moderate sulfur, very little isoA. By comp time it seems to be malt and wheat, big banana, no sulfur, same moderate 4vg. That change is why I wonder if Sulfur Dioxide SO2 or sulfites SO3 can catalyze the synthesis isoA outside of the yeast cell. Seems coincidental that sulfur seems decrease, while isoA increases. In lab production they use sulfuric acid (H2SO4) as a catalyst to convert isoamyl alcohol and acetic acid into isoamyl acetate.
Can one of these sulfur derivatives initiate the synthesis isoA?
Is H2O + SO3~>H2SO4 happening and catalyzing isoA synthesis outside of the cell in the wort?
May have to proposition big monk to scour the research for data.
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