Beer Forum

Hi,
This happened to me a couple of times: I brew wednesday evening. Fermentation starts very aggressively during the night, slows down during Thursday and then stops (no bubbles at all on Friday). Is that normal? Should I wait a few days before checking gravity? Should I do something else?

What temperatures do you have them at? If they get hot, they go apeshit and ferment fast.

Could be a lot of things here. Need your O.G. and yeast strain and how much yeast pitched, temperatures.

barakrot wrote:Hi,
This happened to me a couple of times: I brew wednesday evening. Fermentation starts very aggressively during the night, slows down during Thursday and then stops (no bubbles at all on Friday). Is that normal? Should I wait a few days before checking gravity? Should I do something else?

It can be normal. I've had beers finish that quickly (at reasonable ale temperature). Or it could be abnormal. I used one manufacturer's Oktoberfest strain 3 times and it did that to me each time. I switched to the other guy and no more problems.

The thing to do is take a gravity reading. If the gravity reading shows an apparent degree of fermentation commensurate with what is expected from the particular strain (usually in the 68 - 80% range with 75% being typical) then things are OK. For example if you brew a 12 °P beer using a yeast that is expected to deliver 75% attenuation and you find that you are at 4.8 °P [(12-4./12 = 60% atttenuation] then you know the yeast have ripped through most of the sugar and you can expect a gradual if somewhat less impressive reduction to an ADF in the 70's over the next few days. OTOH if things go like gangbusters for a day or 2 and the ADF is only say 30 or 40% you conclude that something is wrong and take corrective action.

This all assumes, of course, that the yeast are being operated at a reasonable temperature for the particular strain. A lager which reaches 60 - 70% ADF 2 days because you fermented it at 85°C isn't going to be a very good beer.

try adding a can of red bull and vodka, that tends to restart aggressive things that stop!

many thanks for the tips.
i opened - tested gravity it stopped on 2.9% --I stirred and added enzyme . now i see normal behavior. will check gravity in ~ 2 weeks

barakrot wrote:many thanks for the tips.
i opened - tested gravity it stopped on 2.9% --I stirred and added enzyme . now i see normal behavior. will check gravity in ~ 2 weeks

You shouldn't need to add enzymes to get a complete attenuation. In fact, enzymes like beano can end up wrecking an otherwise good beer because it really breaks down all the dextrins and leaves you with a very thin beer. Can you tell us a little more about your process, e.g. extract or all grain, mash temps, OG, yeast type, pitching rate, pitch temp, fermentation temperature, temp swings, etc? Usually the first cause of this is fermenting too warm as the other posters have suggested, but I think we need more information.