Can you add more yeast to your already bottled beer?

You have bottled your beer and let it sit for 2 weeks. You go to check on your bottles and they are still flat! Can you add more yeast to save them? We break it down in this episode of BrewTalk with Mr. Beer.

Imagine that you bottle your beer and then you go to grab one and put it in the fridge and the bottles are soft, it feels like there is no pressure in the bottles at all.

Worse yet, you put one bottle in the fridge and then you go to drink it and its either super flat or it has a slightly off-flavor that tastes like butter or cider. What do you do?

You can add more yeast to the rest of your bottles to either add carbonation to your brew or to help clean up an off-flavor in your beer. There are a few considerations that you need to examine before you do this.

Make sure your bottles aren’t leaking. If C02 is escaping, adding more yeast won’t fix the problem. In these cases, sometimes you can try and rebottle, which is not really recommend as it opens up an entire doorway to infection and oxygenation if not done properly. You also need to add more sugar as what was in there was consumed by the yeast.

So, if you have leaky bottles adding more yeast will not help create any more C02 in your beer.

The other factor is that if your beer has an anaerobic infection adding more yeast won't help. This is basically anything other than that butter or cidery taste in beer that you get from diacetyl or aldehydes in your beer.

If those are not a consideration, then you want to follow this process to add more yeast to your bottles.

  1. Get a packet of fresh, unopened yeast that is the same as the yeast you brewed the beer with
  2. Sanitize and dry a small saucer or plate
  3. Wash your hands VERY well
  4. Sprinkle some yeast in a thin layer on the saucer
  5. Open the bottle and firmly press your fingertip onto the granules so that they stick. (your fingertip should be pretty consistently covered with yeast)
  6. Sprinkle what was lifted by your finger into the bottle
  7. Quickly reseal the bottle and give it a gentle squeeze to assure there are no leaks
  8. Move your bottles to a warm area for 2-3 weeks.

That’s it. Now this might not always work as we listed out the other factors that could be at play when you go to do this, but it never hurts to try.