Extremely quick (almost) complete fermentation?

[Oddpac87]

Hey folks, so I brewed a Porter on Saturday night. Went into the fermenter at around 9:30 PM with an OG of 1.059. When I woke up on Sunday morning I noticed it was bubbling a bit, nothing too rapid, but I figured it would kick up later in the day. Got home that night and it was going even slower, but it felt way too early to bother with taking a reading. Woke up yesterday morning to find no activity at all. Didn't get a chance to take a reading until I got home from work last night and I got 1.020 (target is 1.016). I've only got a couple batches under my belt, but it certainly seems finished to me. ZERO activity from the blowoff, the krausen has fallen.

Now the questions - Could it still be going slow enough that it may drop those 4 points in a few days? Is a few points off the FG even worth trying to re-pitch? Is there any issue that could arise from it fermenting as fast as it did? Am I even right in thinking that was really fast?

 

[sfgoat]

It could definitely still be going. The "active" fermentation may be over but those yeasts are still going to be hard at work cleaning up the leftovers as it were. What temperature did you ferment at? Also what yeast did you use?

 

[johngaltsmotor]

True that was pretty quick but it depends on a lot of factors: fermentation temperature, yeast pitch size, yeast health, fermentability of wort, oxygenation of wort....
Even if it hits target FG quickly you're normally best to leave it a little bit. When they chew through it fast they leave behind some of the complex sugars that take longer to digest still.
For a porter I'd leave it in the fermenter for at least 2 weeks regardless. It's not like an IPA where you are losing hop power from day 1 so the added complexity of letting the yeast work on the remaining sugars will be worth the wait.

 

[Oddpac87]

It could definitely still be going. The "active" fermentation may be over but those yeasts are still going to be hard at work cleaning up the leftovers as it were. What temperature did you ferment at? Also what yeast did you use?

Thanks, that's good to know. Yeast is Safbrew S-33, temperature has been between 61-65.

 

[Oddpac87]

True that was pretty quick but it depends on a lot of factors: fermentation temperature, yeast pitch size, yeast health, fermentability of wort, oxygenation of wort....
Even if it hits target FG quickly you're normally best to leave it a little bit. When they chew through it fast they leave behind some of the complex sugars that take longer to digest still.
For a porter I'd leave it in the fermenter for at least 2 weeks regardless. It's not like an IPA where you are losing hop power from day 1 so the added complexity of letting the yeast work on the remaining sugars will be worth the wait.

Thanks. Yeah, I definitely have no problem leaving it for a couple weeks, that was my plan anyway. I basically just wanted to know as soon as I could if people thought I might need to re-pitch.

 

[Paradingbull]

If you can warm it a bit to around 70F for 3-4 days it will help your yeasties finish up.

 

[Oddpac87]

If you can warm it a bit to around 70F for 3-4 days it will help your yeasties finish up.

Yeah, that shouldn't be a problem.

Thanks for all the help, folks.