What is the fastest fermentation you have experienced?

[stosh]

I brewed last Saturday. Used a starter with some harvested yeast and fermentation started on Sunday 10-12 hrs later.

I noticed the airlock stopped bubbling late Monday afternoon. I know enough to not judge fermentation only by air lock activity but...

Curiosity got the best of me and I popped the top to take a gravity sample. It smells good but burned my nose (this is a low grav brew around 6%). The gravity ended up to be 1.008 but the krausen was still on top. I'll take a few more gravity samples and judge fermentation by that.

Is the 'burning' sensation from CO2?
Can fermentation be done and still have the krausen on top?
What is the fastest fermentation you have experienced?

 

[thehaze]

Yes, fermentation can be done and still be krausen on top. Some yeast exhibit that behaviour, but it's nothing to worry about. I have had beer to reach final gravity in less than 3 days, so under 72 hours. But I think most are almost done by day 3. It depends on so many things, but up to 7-8%, it should be done in 5 days tops...

It is normal for the smell in the fermenter to " burn " your nose... Brew on.

 

[IslandLizard]

Yup, the burning in the nose is CO2.
What temperature was this fermenting at?
It takes a day (or more) for the krausen to sink after (active) fermentation is done. There is a conditioning phase that follows active fermentation. For most, if not all beers, that's an essential part of the process too.

I've had a NEIPA going from pitching to glass in 4.5 days doing a large single dry hop 24 hours in. The beer had attenuated to 70% of its target already. I used a large pitch of WY1318, a good dose of O2, and fermented at 67F. It included a day of cold crashing, forced carbonation (rolling keg) and 18 hours of carbonation stabilization. Fresh and delicious!

Together with my culinarian partner we won the club's beer and food pairing competition! Everyone loved the beer. 2 weeks later I took it to our State Homebrewers Guild's picnic. More than a few people said it was one of the best beers there. The keg nearly kicked.

 

[catdaddy66]

I honestly can't say what my fastest fermentation was, as I never want to rush it. I let all of my beers sit for two weeks to finish (some 3-4 weeks) becoming beer. If I brewed smaller batches than my normal 5 gallons then I could experiment with the "grain to glass" times, but after reading the wealth of info on HBT I decided long ago to allow other more scientific members to glean this knowledge. I will acquire it the old fashioned way... Study!