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Solutions to excessive fermentation

  • 21-10-2021 9:10am
    Registered Users Posts: 1,938 ✭✭✭

    Hi all,

    I am going to preface this with I know that there is a risk of infection from opening the bucket lid!

    Some of the kits I have brewed fermented excessively at the start, and even with a 30l bucket when brewing 23l kits I have found that the air lock gets blocked (probably by the krausen) and caused problems such as liquid leaking out of the air lock bung.

    Question 1: Outside of the risk of infection, would there be other issues starting at 20L (for example) and then add 3L of water and gently mixing when things have settled down?

    Question 2: A kit I brewed recently came with 2 sachets of yeast (Russian Stout). Would it have been okay to add 1 sachet at the start and then add the 2nd after a few days? Or as a more general question, add part of the yeast at the start and add the remainder after a few days?

    Thanks in advance,



  • Moderators, Recreation & Hobbies Moderators Posts: 11,823 Mod ✭✭✭✭BeerNut

    1. There's a slight risk of oxidation from mixing anything in, and the earlier the better, but I have done this with no ill-effects. Boil then cool the added water to minimise infection risk.
    2. Probably not. Dried yeast does suffer from low viability, so if the kit maker says to use two sachets, definintely use two. Under-pitching could mean it doesn't take off properly at all, and stressed yeast in a high-gravity wort can give off-flavours.

    In general, a busy fermentation is healthy and is something you should adjust your system to deal with rather than try and prevent. For a start, don't seal the bucket and attach the airlock at the beginning. You don't need to do either at all, but it sounds like they're just getting in the way. The fermenting beer only needs to be covered to stop stuff falling in, there's no need to seal it. If you like the bubbling of the airlock (and it's purely cosmetic, the airlock doesn't really tell you anything useful) then fit that after a few days when things have calmed down. I got one of those big rubbery builders' trugs to put my fermenter in so that it can overflow happily and the spillage is easily cleaned.

  • Registered Users Posts: 1,938 ✭✭✭randomname2005

    Beer Nut, what would we do without your knowledge. Thanks for your help.

    I will look into a big tray of some kind. I would feel weird leaving the bucket open in case of flies and such like being attracted to the sugary smell. Maybe put a bowl upside down over the air lock hole to keep them out and let the beer do what it needs to do.

  • Moderators, Recreation & Hobbies Moderators Posts: 11,823 Mod ✭✭✭✭BeerNut

    Yes, fly-proof is as sealed as it needs to be. A bowl over the lid hole should do it.

  • Registered Users Posts: 1,351 ✭✭✭Cloudio9

    I'm curious about your fermentation temperature. Generally, a higher temp will get you a more vigorous, faster fermentation. I would normally try and ferment ales below 20C. I believe kit instructions can state quite high temps. Reducing your fermentation temp would avoid meddling with the process and may actually give you a better beer.

  • Registered Users Posts: 1,938 ✭✭✭randomname2005

    I usually try to ferment as low as possible, aiming for 20C as a goal. The stout I mentioned before, which I started last weekend, was pitched at 20C but went up to 23/24C when at its peak fermentation and is now back down to 18-20 and still bubbling away (although a lot slower). At present I don't have a way of keeping beers cooler than room temperature outside of putting them on a cold floor.

    The yeast I used in the stout, HBC Rambunctious Russian Stout, was Safale 04 which gives a range of up to 25. Seems crazy high to me.

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  • Moderators, Recreation & Hobbies Moderators Posts: 11,823 Mod ✭✭✭✭BeerNut

    At 25 the yeast will be happy, but farting out fruity esters to an extent that you might not be when you drink the beer.

  • Registered Users Posts: 1,351 ✭✭✭Cloudio9

    Safale 04 has a reputation as a lightning quick fermenter so fermenting at the top of the temp range is likely to be your issue. If you have the option of fermenting the beer in a room with the radiator off, that usually works pretty well at this time of year

  • Registered Users Posts: 1,938 ✭✭✭randomname2005

    Nice way of putting it!

    It is in the coldest place I can put it, as close to an outside wall as possible, with no heating on.