Many craft breweries and homebrewers enjoy incorporating fruit flavors into their beer fermenting tanks, especially during the hot summer months. Beer is good, fruit is good… Beer with fruit in it is even better! Every spring and summer season, we receive many questions about how to safely add fresh fruit to a brew during fermentation, but after high Krausen has passed, without introducing unwanted infection.
Sure, you can always use store-bought or pre-pasteurized purees, but if you have access to fresh, local fruit, it would be crazy not to use them in your beer! Luckily, preparing fresh fruit to add post-boil is pretty easy! You may have heard of the “vodka tincture” method for things like citrus zest, but what about larger quantities of fleshy, bulky fruits like peaches or strawberries? Well, that is what we will discuss today!
Allow me to paint you a picture. It is a beautiful weekend day, and you just picked several pounds of juicy, fresh peaches with the intention of adding them to your beer. Now you’re wondering, “How do I handle these peaches so they don’t spoil my beer?” There are a couple of ways to get the job done, so here we go!
This is a great low-heat pasteurization method that you can do in a double boiler. First, wash, pit, and puree your fruit. In a double boiler, hold the mashed fruit at around 150-170°F for about 15 minutes while stirring occasionally with a sanitized spoon to maintain consistent heat throughout the mixture. This method should remove most unwanted bacteria. Let it cool a bit before adding it to your fermenter.
In my opinion, this is the most reliable method, but be careful not to overdo it. Your goal is not to cook the fruit but only to sanitize it. Overcooking fresh fruit may cause a loss of the wonderful flavors that make using fresh fruit desirable. Overcooked fruit can also release more fruit pectin, which can contribute to something called “chill haze.”
In my opinion, this method is slightly less ideal as it is not as reliable and requires more work and patience. The advantage of using this method over the low-heat method is that some believe it maintains even more of the fresh fruit flavors. Personally, I find the difference to be negligible in most cases. If you wish to use this method, start by prepping the fruit the same way you would for the heat method. I like to add an ounce or two of very high-proof alcohol to the fruit in the blender. This helps to add a little extra sanitation power without diluting the flavor. Once blended, you will need a sealable container or bag that can tolerate being frozen and thawed multiple times. Transfer the pureed fruit to your container and place it in the freezer until completely frozen. After it is fully frozen, remove the container, let it thaw, then place it back in the freezer and repeat this process at least 4 times. This method is said to damage the cell walls of bacterial organisms, rendering them weak and unable to reproduce. Once you have completed this freezing and thawing process, the fruit can be added to the brew during fermentation.