With proper care, beer can potentially stay fresh in a growler for as much as two weeks (although, who would let that happen?). If not taken care of, beer can begin declining in quality within hours. Follow these suggestions for best results.
Double check your cap is tight.
Your server will always attempt a snug cap but nobody’s perfect one hundred percent of the time. Double checking is a quick and easy way to ensure quality in your growler. The tighter the cap, the better it will protect the beer.
Keep growlers out of the sun.
UV light from the sun will both warm up the beer and will react with the beer causing it to become “Lightstruck”. This will make the beer smell skunky. Stainless Steel and Ceramic growlers will prevent the issue while brown glass will delay the time it takes. Green and clear glass blocks very little light.
Keep the growler cold.
This will ensure that the beer stays carbonated. Growler caps are not capable of fully containing significant amounts of built up pressure from escaping the bottle. As beer warms up, it will release a lot of carbon dioxide which the cap will not be able to prevent. Keeping the beer cold at all times before consumption will ensure the best quality for the longest amount of time.
Consume in a single day.
When beer is poured from a growler, oxygen enters in its place. This will lead to oxidation in the leftover beer which causes a stale taste, often “cardboard like”. Depending on the beer style, the beer can also change colour.
Keep capped until your first opportunity to rinse.
A growler left open with beer inside will allow the beer to dry and stick to the sides. This makes it very difficult to clean and often will require a lot of soaking to free up deposits.
Rinse well (2- 3 times) with HOT water.
Assuming the beer has not been allowed to dry out, growlers will clean up well with two or three good, thorough rinses of hot water. Soap is not needed and it is extremely difficult to remove well enough from a growler. It will kill head formation on your next fill and in more extreme cases, cause your next fill to taste soapy.
Throw the cap away.
Breweries will not reuse a metal cap and will throw it away before the next fill anyway. Capping a clean growler will prevent it from drying out properly which will often lead to a warm, humid environment inside that is perfect for bacterial growth. Nobody wants that.
Allow to dry, ideally, upside down.
Upside down will give your growler its best draining and drying opportunity. If this isn’t a practical option for you, make sure you pour out any pooled water that remains in the bottle after the rinse. Once dry, the growler will be fine to wait for the next fill.