Wort has started fermenting again on its own

Discussion in 'General Beer Brewing Discussion' started by DrTorrent, Nov 28, 2019.

Help Support The Homebrew Forum UK by donating:

  1. Nov 28, 2019 #1

    DrTorrent

    DrTorrent

    DrTorrent

    New Member

    Joined:
    Nov 28, 2019
    Messages:
    3
    Likes Received:
    0
    Hello all! Firstly, I’m new to the forum and world of brewing, although I am familiar with some elements due to friends being in the hobby.

    Moving on to the issue I’m having, I was recently gifted a brewing kit by a friend from Brewdog which is an all grain kit. Yes, all grain brew for a first timer. Brave. I know!

    The kit states the brew should take two weeks before bottling. Up until a few days ago it looked to have settled down, with a dark brown colour and the expected sediment. But a couple days back it changed to a light brown colour. And now, has started bubbling again and even looks like it’s started to carbonate in the fermenter due to a head appearing and what looks to be occasional bubbles rising to the top. I haven’t done anything to it, moved it or added anything. I am due to bottle it in two days so I’m wondering why this has happened.

    It is only a small brew in a one gallon glass jug which has been kept in a dark cupboard where it has been warm enough to ferment. Hopefully this isn’t a failed brew.

    Do any you experienced brewing folk have any idea what could have happened here and what I should do next?
     
  2. Nov 29, 2019 #2

    foxbat

    foxbat

    foxbat

    Junior Member

    Joined:
    Nov 24, 2013
    Messages:
    1,892
    Likes Received:
    929
    Location:
    Essex, UK
    Its started fermenting again. The question is what's doing the fermenting?

    You can't reasonably stop it and you can't bottle while it's active so it's best to leave it until it's finished then take a sample, measure the FG and taste it. If it tastes good and the gravity isn't unreasonably low then you're OK.
     
  3. Nov 29, 2019 #3

    GerritT

    GerritT

    GerritT

    Landlord. Supporting Member

    Joined:
    Jul 27, 2017
    Messages:
    2,295
    Likes Received:
    748
    Welcome to the best hobby on earth!

    I have several of those small glass demijohns around (I think they look beautiful, by the way) and I feel the pain of taking a sample and measure the gravity. But sadly it's the only way to find out if it has reached 1010 (or wherever it is supposed to land on). You could wait for a few more days (probably even a week without side effects, but measurements will have to be taken.

    Nightmare scenario: a wild yeast or bactery has entered the demi and started working. If I suspected that in one of my brews I would surely wait another week. You don't want to bottle a brew suspected of infection.
     
  4. Nov 29, 2019 #4

    the baron

    the baron

    the baron

    Landlord.

    Joined:
    Oct 13, 2013
    Messages:
    1,282
    Likes Received:
    441
    Location:
    castleford
    Are you sure it is fermenting as the change in colour could be that it is clearing and dropping the last sediment also is it possible that the co2 being released is causing the bubbling? Have you taken a hydrometer reading and if it has started fermenting again which is unusual for a wild yeast to get hold after it has done its normal fermentation. Have you been lifting the lid etc as a normal fermentation would have not allowed the wild yeasts to dominate the fermentation so it does sound as if it has been re-introduced if it is actually fermenting. Ps do not bottle until you are sure it has stopped fermenting
     
  5. Nov 29, 2019 #5

    Justin Dean

    Justin Dean

    Justin Dean

    Regular. Supporting Member

    Joined:
    Mar 22, 2019
    Messages:
    268
    Likes Received:
    54
    Measure with hydrometer until you have static level for 3 consecutive days and then you know it is finished, patience.
     
  6. Nov 29, 2019 #6

    Grealish

    Grealish

    Grealish

    Well-Known Member

    Joined:
    Dec 26, 2018
    Messages:
    150
    Likes Received:
    69
    I brewed a small beer with the leftover grain from a proper brew once and it sat around for months in the fermenter. After a while, I noticed airlock activity. When I finally bottled it, it was about 1000 (so the ABV was no longer low!) and it was disgusting so I put the second fermentation down to an infection. It was ok for cooking with, though. The difference is, yours is less than two weeks in.
     
    crowcrow and GerritT like this.
  7. Nov 30, 2019 #7

    dwhite60

    dwhite60

    dwhite60

    Active Member

    Joined:
    Oct 20, 2019
    Messages:
    60
    Likes Received:
    23
    Location:
    Garner, NC, USA
    Sometimes yeast will stall for some reason then re-start. Don't panic.

    All the Best,
    D. White
     
  8. Dec 1, 2019 #8

    Harbey

    Harbey

    Harbey

    Regular.

    Joined:
    Aug 12, 2018
    Messages:
    288
    Likes Received:
    83
    Location:
    Scarborough UK
    Just be patient. It's the hardest part of the whole process. I imagine your yeast is just cleaning up after itself and you'll be left with a nice, clear beer.
     
  9. Dec 1, 2019 #9

    trummy

    trummy

    trummy

    Active Member

    Joined:
    Feb 25, 2017
    Messages:
    28
    Likes Received:
    4
    Location:
    East Midlands
    Taste it! If its off throw it - If not let it ferment out. Change in colour, is that because its starting to clear?
     
  10. Dec 2, 2019 #10

    DrTorrent

    DrTorrent

    DrTorrent

    New Member

    Joined:
    Nov 28, 2019
    Messages:
    3
    Likes Received:
    0
    Thanks for the responses guys! Seems like a great community here!

    I have left the wort some time longer and the airlock activity seems to have stopped, the "head" I described seeing is now non-existent and the wort itself seems to have cleared itself up again! Worry over, it would seem! I was worried that something foreign had found itself in there despite me being very careful to sanitise and never removing the airlock. Fortunately, it looks to have been part of the primary fermenting state, but seemed to significantly increase in activity all of a sudden, causing the sediment to cloud it up again. I will be looking to bottle in the next day or two. Stay tuned! I will keep you folks updated.

    Before I go, quick fire question. How much is the ideal amount of dextrose for priming in a 500ml bottle for an IPA? From what I could find reading around, the right amount would be about a teaspoon and a half per bottle. Would you agree?

    Thanks!
     
  11. Dec 2, 2019 #11

    terrym

    terrym

    terrym

    Member

    Joined:
    Apr 12, 2015
    Messages:
    5,043
    Likes Received:
    2,575
    Location:
    North Sussex
    I would say that's far too much.
    For a 500ml bottle, at most one level tsp, better about 0.75 tsp. I reckon one tsp is about 4.5 g.
    I suggest you start to use this which will give you a much better idea of how much priming sugar you should be using
    https://www.brewersfriend.com/beer-priming-calculator/
     
  12. Dec 3, 2019 #12

    DrTorrent

    DrTorrent

    DrTorrent

    New Member

    Joined:
    Nov 28, 2019
    Messages:
    3
    Likes Received:
    0
    Thank you
     

Share This Page