Adjuncts and sanitization

Hi,

I've never brewed with fruit before and I've come across a blueberry porter recipe that I'd really like to try.  It says to microwave frozen berries to break open the skins and release the flavour - and also partially sanitize them.  Any tips on how to fully sanitize them?  I was thinking about just heating them on a pot on the stove, letting them cool to room temp, and then adding them.

Yes, heating to 160 degrees F for 15 to 20 minutes will do the trick.

Thanks Kevin.  I'll do exactly that

Kevin58 said:

Yes, heating to 160 degrees F for 15 to 20 minutes will do the trick.

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Seems hot and long.

At 161oF, pasteurization happens in under 1 minute. Holding fruit at 150oF for 15 minutes should do the trick, then you want to cool the fruit as fast as possible so that it doesn't dwell in the temperature zones where new flora can flourish. I'd accomplish this by flashing whole berries in 170oF water for 15 seconds, followed immediately by cooling in crushed ice. This'll preserve the flavor integrity and get rid of surface flora. After all, the inside of the fruit doesn't need to be heated if the skin is good.

Berry fruits tend to be under 4.6 pH, which lowers the temperature needed for pasteurization. If you're going to use lower temperatures and longer time to pasteurize, you can break down the berries before they get to temperature. An additional control is to check the pH and adjust to 4.2 to 4.6 pH with either citric or tartaric acid.