I put a batch on last Sunday, started off with a crazy high reading on the hydrometer (around 1080 when I was expecting 1040ish according to the kit) - though I suspect that was because I drew a sample through the tap and got all the heavy stuff from the bottom.

Either way, it's been a cold week and I've been trying to keep the sucker warm, but it's been down around 18-20 quite often — there haven't really been any indicators of fermentation but I have taken daily measurements and after getting around 1050 on the first day I seem to be getting around 1040 today - the taste has also mellowed over the week leading to me to believe something was going on ok.

I get the feeling my fermenter doesn't have a great seal, and yesterday after a cold night I gave it a swirl after getting the room warm and I suspect I might have ended up with some bad guys in there, today the sample was slightly fizzy and there's a hint of a sour taste starting to come in. Should I just ditch it now and start with a lager better suited to the current temperature, or can it be rescued?

  • The high gravity reading is probably from not stirring the wort after adding top up water. May 6, 2012 at 15:42
  • did you see a krausen develop - a white foam maybe with brown green floating things. that's a reliable indicator of fermentation.
    – mdma
    May 6, 2012 at 19:28
  • No foam really - that and the low temperatures are what prompted me to make regular hydrometer readings, to see if something was actually going on in there.
    – Matt Lacey
    May 6, 2012 at 23:16

2 Answers 2


My first suggestion would be to stop taking daily measurements. I usually do my first check at 7 days just to see how things are going, then leave it be for another week or two before I molest it again.

18-20C is just fine for for ale ferments. By my calculations, that's 64.4-68F, which is where I ferment all of my ales.

As for the sour flavor, I wouldn't worry about it after 6 days. You can get some very odd flavors in the various stages of fermentation. You also don't need a hermetic seal for primary fermentation. I've used plastic cling wrap or aluminum foil in lieu of an airlock several times in the past.

So in short, my advice is to let the yeast do its job and clean up after itself. Give it another week, check the gravity again to see if it's progressing, then give it another week or two before testing again. You might be pleasantly surprised.

  • So three weeks wouldn't be a problem? Because I was expecting around 6-7 days I didn't factor in the fact that I'll be away for 5 days from day after tomorrow, which is 10 days in to the brew in total — so maybe just leave it until I get back and hope for the best?
    – Matt Lacey
    May 6, 2012 at 23:17
  • That's certainly what I would do. I've learned that extra time in the primary will usually improve a beer.
    – JoeFish
    May 7, 2012 at 2:22
  • Cool, thanks for the advice mate. Had it in my head that if it was in there too long it'd almost be guaranteed to get infected. This is why I love Stack Exchange. Ok, won't touch it for a week, though I might get a heating belt just to ensure it doesn't get way too cold :)
    – Matt Lacey
    May 7, 2012 at 4:48
  • 1
    Yeah you'll see a lot of bad advice in various places telling you to rack your beer off the primary after 5-8 days, but that's total garbage and it seems like most of the steady posters here will tell you as such.
    – GHP
    May 7, 2012 at 13:21
  • 1
    Great, glad to hear it! Once you get it in the bottles and conditioned for a few weeks, I think you'll be happier with the flavor. Age cures many beery ills. Or at least helps ;)
    – JoeFish
    May 15, 2012 at 20:45

For brews with high OG I recommend leaving the beer un-measured for 14 days then take a few daily measurements if you want to check progress. A temperature of 18-20 degC is perfect for yeast ferments. I would not personally aim to ferment above 24 degC (or even 22). Racking off to a secondary vessel after at least 10 days fermenting is sometimes useful to facilitate clearing and to promote a slightly sharper taste. As other note there is no need and little reward in trying to do anything too quickly. "More haste - less taste" is my maxim.

Unless it really tastes like vinegar I would always bottle or keg a brew. It usually improves with age and "undrinkable" beers are often perfect after 6 - 8 months conditioning.

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