If you’re like me, then you’ve probably assembled a small arsenal of growler jugs over the years. Some inevitably break, but many remain structurally sound well after we’ve relegated them to a shelf or retired them in favor of some fancy new model with a handle and a swing top.

Brewers are, however, a resourceful lot, always searching for ways to reuse old stuff. Here are five uses for your old growler.

1. Make a yeast starter.

A growler jug is an excellent vessel in which to propagate yeast. At 64 ounces (1.9 liters), it’s just the right size for building starters for all but the biggest beers. While you can’t heat a growler directly on the stove as you can an Erlenmeyer flask, it’s simple enough to prepare starter wort in a saucepan, chill, and use a sanitized funnel to direct the barley water into the sanitized jug.

2. Run a blow-off tube.

High-gravity wort and aggressive yeast strains conspire to make your carboy floweth over. When a simple airlock won’t cut it, run a blow-off tube out of the fermentor and into a growler jug filled about one-third full of the sanitizer of your choice.

3. Experiment with ingredients.

Have a wild hair to brew a star anise porter or dry hop with carrots (I bet someone has tried it)? Don’t risk screwing up five gallons. Instead, pull a small portion of a tried-and-true recipe into one or more growler jugs. This is also a great way to experiment with different yeasts or dose the same beer with different dry hops. Each growler jug holds enough beer for 5 bottles, so you can have fun without fearing commitment.

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4. Conduct a forced fermentation test.

This is one of my favorites. You know you’re not meant to rack your beer until it has reached final gravity, but how, exactly, do you know what that target value is? A forced fermentation test will tell you. After you’ve cooled your boiled wort, reserve about half a growler’s worth (32 ounces, or roughly a liter) when transferring to the fermentor (you can bump up the batch size to compensate if you like). Inoculate with yeast, and either place the growler on a stir plate or plan to periodically agitate it. And keep it warm, even if the main batch of beer is a lager. The idea is to get those yeast cells to ferment their little hearts out in your mini-batch of beer. It’ll finish out in a couple of days, and the final gravity of this small batch tells you the lower limit of attenuation of the main batch. This number represents the absolute lowest final gravity these yeast cells are likely to achieve. So, if the forced fermentation test bottoms out at 1.010, and the main batch stops at 1.012, you’re probably done. If the main batch hits only1.016, it may need rousing and a few more days to eke out those final few gravity points.

5. Take beer to go.

Okay, so this one isn’t so creative, but hear me out. Most of us who switch from bottling to kegging never look back, but bottles are nice for taking to parties or stashing in a cooler in the trunk to enjoy after a long hike. It’s a bit harder to do this with a keg. But, you can always use the growler for its intended purpose and take some fresh draft homebrew with you. Problem solved.