Can you open the lid during fermentation? (4 Important Watch Outs!)


Homebrewing beer is a hobby that requires a lot of patience and it can become quite difficult to resist the urge to open the lid during fermentation to take a peek or make sure everything is going according to plan. With this in mind, I thought that I take a closer look at this impulse to see if there are some watch-outs to be aware of!

It is perfectly fine to open the lid of your fermenter to check the process or take a gravity reading provided that you take the proper precautions to sanitize all equipment used, minimize the amount of oxygen added to your wort, and re-seal the fermentation bucket fairly quickly to avoid contamination.

Since fermentation is such an active process it is only natural to want to observe what is happening and react to it as needed. At some point, you’ll also need to take a gravity reading for your beer to help determine whether or not fermentation is complete and calculate the alcohol content. Let’s explore this question in more detail and go over some best practices!

Can I take the lid off my fermenter or open my fermentation bucket?

The short answer is yes.

There is no rule against taking the lid off of your fermenter but you should always have a fairly good reason for doing so. That’s because there is a risk anytime you remove the lid to your fermenter that you could cause problems with your batch of beer.

Here are the two biggest potential issues:

  • Wild yeast or bacteria could contaminate your beer – These could come from the open air or the tools you use to take readings, stir the wort, or anywhere else.
  • Excess oxygen could enter your beer if you shake it around or stir it up – While oxygen is great for the wort right before fermentation to help the process along, you want to avoid it after it is complete to avoid off-flavors produced by the oxidation process.

I should really point out that the risks of either of these things happening is really quite low if you are careful while you work.

Generally, the risk of bacterial infection is highest at the beginning of fermentation (before there is alcohol present) and the risk of excess oxygenation is highest at the end of fermentation (when there is less CO2 being produced inside the vessel).

So, how should we handle taking the lid off?

4 important watch-outs when removing the lid of the fermenter

Anytime you are thinking of taking the lid off, first, ask yourself whether or not you really need to do so. If its important enough, then you’ll need to follow these best practices to ensure that you don’t make a mess of your batch!

  1. Sanitize anything that will be touching your beer including spoons, wine thieves, hydrometers, cups, whatever.
  2. Go ahead and sanitize the rim of the lid just in case.
  3. Avoid mixing or stirring the wort (unless it is an extreme case of a stalled fermentation etc.).
  4. Put the lid back on as soon as you’ve finished your work.

If you follow these guidelines then you will likely be just fine taking the lid off of your fermenter.

How do you open a fermentation bucket?

There are many different kinds of fermenting vessels but a bucket is one of the simplest and most common ones to find.

Typically, these will have a large lid that covers the top along with a whole in the middle-sized for a rubber bung that you’ll attach your airlock to during fermentation. If you have a wine thief and the hole is big enough, it’s actually best to go ahead and remove the bung, dip the wine thief in for a sample, and then simply replace the bung when you are done. This will minimize all risks, assuming that your equipment is sanitized.

Otherwise, you will need to remove the entire lid (be careful not to spill the sanitizer out of your airlock if you have some there) by prying off up one side and carefully ringing your finger around the lid so that it all comes off at once.

For future batches, you could opt to add a spigot to your fermenting bucket so that you can easily pullout a sample to measure without having to worry about introducing too much potential contamination. This can also help when it comes time to bottle. However, it can be difficult to keep spigots clean, especially plastic ones, so take extra precautions if you go this route.

Can I stir during fermentation?

It is usually best that you avoid stirring your wort during active fermentation to avoid excess oxidation in your beer. In fact, there is really no reason to want to stir your beer if you have achieved an active fermentation.

However, it is acceptable to stir right after you have added your yeast or if your fermentation appears to be stuck for some reason and you are trying to restart the process.

Be sure to sanitize your stirring spoon and avoid splashing the spoon into the wort, minimizing aeration.

What is open fermentation?

Since we have focused so much on keeping the lid on your fermenter you might be wondering why some people practice open fermentation. Essentially, open fermentation just means that there is no sealed lid or cover for your beer while it is fermenting so that it is left open to the air.

There are a few reasons that a homebrewer might want to do this and usually it’s because they are intentionally trying to infect their beer with wild yeast strains or bacteria. This is a pretty common practice for ‘farmhouse’ beers or other wild beers.

In the vast majority of cases, however, you should avoid open fermentation for your beer and keep things nice and sealed up!

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