Sorry for responding to a very old thread, but this is an important issue that everyone will benefit from.
Originally Posted by deanocamino
I have a wheat bubbling a way and plan on adding some passion fruit juice to the secondary tomorrow. My thoughts were to boil any fresh fruit or fresh juice that I add, just to get the nasties out.
The first time I did this with a partial raspberry and blueberry ale. I just tossed the thawed berries in the mix doing nothing to them. I caught a nasty infections while doing so.
I know you can use those canned juices but I had the real deal lying around and did not want to ruin my beer. I have read to boil it in water or boil the fresh juice for like 2 minutes and let her cool down.
I also make wine, so my advice comes from the mixed experience. LOL
Juice is not an issue if you trust the canner/supplier. But if you don't I would follow the second piece of advice below.
The hard way -
Freeze the fruit you are going to use, then put it in a sterilized pan (because you are not going to boil it) and raise the temp to 165F for 15 minutes (I add pectin to make sure the fruit will break apart in the secondary). Cover and let cool, then add to secondary in a bag (make sure it is not packed tight).
The long (preferred way) -
Make a mini must (the wort equivalent for wine making). Mash (physically mash it - not mash as in beer making) the fruit in a sanitized bucket. Add some water so the consistency is like a puree. Add a crushed campden tablet for each gallon of must. Stir it with a sanitized spoon. Loosely cover this and let it sit over night (I cover it with a clean towel). The campden tablets will kill the nasties and prevent the fruit from browning. The next day add the fruit to the secondary in a bag. Make sure it is not tightly packed. This works the same for questionable juices, just stir the tabs in, cover, and wait.
I hope this helps.