I started my first cider yesterday. I am concerned that, because I haven't pasteurised I am running the risk of getting 12 litres of vinegar.

Is there I anything I can do, now fermentation has started, to prevent that and how can I keep tabs on progress during the fermentation?


The test for acetobacter is simple: smell whatever's coming out of the airlock on your fermenter. If it smells like vinegar, you've got bacterial contamination ["an infection"] :).

For a fermentation in progress, there's only a couple of options. You could pasteurize the whole batch, which would kill off bacteria as well as the yeast, so you'd have to repitch your yeast.

Another possibility is to dissolve some campden tablets into your cider. If you pitched a quality, healthy yeast, they won't be affected by the increased sulfite concentration but it will inhibit bacteria and wild yeast growth. If you take this route and find fermentation stops, just give it some time and repitch, as the sulfites from the campden will dissipate with time. Campden tabs are used all the time in wine and cider making to prevent infection without having to boil/pasteurize.

  • SO if the fermentation has been going a day or so, I can still add campden tablets? how long till I should see bubbles in my air lock again? Should I stir it in?
    – Mild Fuzz
    Nov 26 '13 at 14:16
  • 1
    Yep, you can still add them. At the typical dosage of 1 tablet per gallon of wort / must, it takes about 24 hours for the sulfite to outgas and dissipate. After this your yeast should rouse themselves. It should be crushed and stirred in. I find it easiest to dissolve it in a small amount of liquid and then stir that liquid into the batch. Even though the campden will kill most of the nasties, it's still important to follow sanitation procedures during this step and minimize splashing to help prevent oxidation.
    – mallan1121
    Nov 26 '13 at 16:24
  • Okay, so it just smells of yeasty apple juice at the moment. Not a whiff of vinegar at all. I'm assuming this is to be expected, and I should go ahead and add the tablets? Or would you expect to smell it now if it was going to turn (fermentation began sunday night/monday morning)
    – Mild Fuzz
    Nov 26 '13 at 18:43
  • 1
    I am tempted to not do anything. It smells fine, and my instinct says it is okay. Is this folly?
    – Mild Fuzz
    Nov 26 '13 at 22:51
  • 1
    Not at all, not doing anything is often the best policy in this hobby, and if I were you that's exactly what I'd do in this situation. Most often it's best to just let the yeast do their work.
    – mallan1121
    Nov 27 '13 at 0:19

I believe Acetobacter will spoil your product only if there is an oxygen present. So, to prevent that, good airlock would be enough. Once fermentation is in progress, there should be enough CO2 to push the air out, even if airlock is poor.
As fermentation slows down, CO2 will be produced in smaller quantities and demands to airlock qualities became higher. I generally fill my airlocks with some sulfite solution to prevent oxygen diffusion and I believe this is enough.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.