Fermentation Done After 2 Days?

Question

Fermentation Done After 2 Days?

Haney

2014年12月6日 16:13

So this is a weird one.

3 weeks ago I made an Xmas beer. I brewed it, pitched the #2 yeast, and put the carboy in my cold dark room (about 70 F) to ferment. The fermentation and krausen began about 18 hours after brewing, and lasted for 6 days or so. I measured the FG and it was spot-on so I continued as planned. All was well.

I really like the recipe so I brewed another batch 2 days ago (on Sunday). I pitched the #2 yeast and again put the same carboy in the same dark room at the same temperature. Again, the fermentation / krausen began about 18 hours after brewing. However, tonight I took a look at the carboy only to find that the krausen has completely sunk to the bottom... 4 days earlier than the identical recipe did the last time.

What happened? It's still fermenting given that I can see the 3-piece airlock bubbling, but what is the deal with the super early krausen drop? I'll give it 7 days, measure the FG, and hope for the best, but can anyone explain the reason that batch 1 went 6 days before the krausen dropped and batch 2 went less than 48 hours?!

Topic primary-fermentation krausen yeast fermentation homebrew

Category Mac

tinypriest · Accepted Answer · 2014年12月6日 15:35

Many factors:

Was the 2nd yeast of the same lot code?! Yeast is finicky and may simply not react the same way twice if anything is even slightly different in your mix.
Was the malt extract exactly the same as the 1st batch? Dry vs. liquid, fresh vs. 2 years old? Anything different in how you prepared additions like Chrystal malt, etc.?
Any differences in the boil? EG: Longer or shorter boil time? Longer or shorter time to cool to room temp? Partial boil vs. full volume?
Did you change your water in any way? Did it come out of the cold-water tap as before or did you use another source, such as mineral water from a 5 gal container?
Did you aerate the wort in exactly the same way the 2nd time?

The fact that fermentation continued means you are probably ok, though any of the above factors might have made it taste slightly different from the first batch. But without industrial quality control of our kitchen or basement environments that's unavoidable and makes homebrew such a joy :)

Henry Taylor · Accepted Answer · 2014年11月26日 05:26

Use a sterile wine thief to get a sample and take a specific gravity of your current product. How does it compare to the final gravity of your previous batch. Since fermentation is still proceeding, we can guess that you haven't reached your target gravity yet. Which means the krausen is heavier that it was last time...

Possible causes...

Did you use different water, or treat your water differently in preparation for the second batch?

Given that it is an Xmas beer, are there any components with limited shelf life? Fruit augments can act differently depending on their freshness. Even if proper sterility is maintained, the chemical make up of ripe fruit is different from that of green fruit.

The white elephant in the room is infection. Are there any off-smells? Aside from the fallen krausen, does your product look any different than last time? Are there more free floating particles than usual? How is the color?

I would suggest that you let the fermentation complete as normal, and see what the result smells like? If you still have a bottle of the previous batch, use it as a basis for comparison (smell, color, taste). Chances are that it will be fine. Small differences happen all the time between batches; after all, yeast is life and life can be unpredictable.

Fermentation Done After 2 Days?

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