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Raspberry Wheat Secondary Fermentation

Hey all!

This is my fourth brew, but my first adding fruit. Using the NB Raspberry Wheat kit, but I want to flavor with real raspberries as opposed to the extract.

Brew day was last Wednesday, and primary fermentation in 6.5gal BMB started within 30 hours. Bubbles in the airlock have slowed to once every few minutes, so I’m thinking my primary fermentation is coming to an end. I don’t have a hydrometer (yet).

For secondary fermentation, I want to transfer off of the yeast cake, but I’m thinking my 5gal BMB won’t leave enough head space for 2.5lbs of frozen raspberries, epecifically if the sugars in the raspberries cause an active secondary fermentation. Should I transfer to my 5gal, clean and sanitize my 6.5gal and transfer back into 6.5gal over raspberries in a sanitized mesh bag? Seems like I’m creating a lot of work for myself, but will it be worth it in the long run?

Once I have it over my raspberries, I’m thinking 2 weeks secondary fermentation with fruit, 2 weeks secondary fermentation without fruit.

Thoughts? All advice is appreciated.

I never use fruit in beer, but my concern would be cleaning or sanitizing the fruit first. Don’t want anything bad happenings in the ferm. Get a hydrometer first so you have it on hand to check.

I’ve read mixed suggestions when it comes to sanitizing fruit for secondary ferm. A few have recommended to boil at 150-165 degrees for 20 minutes. Others have stated that not sanitizing the fruit shouldn’t have any negative effect on the beer.

How much volume is in your primary? Your going to lose some volume to trub so I would just rack it over to your 5 and call it a day. If you have alot leftover rack it into a growler and put a airlock or balloon on it and ferment separately or just bottle it as a weissbier no fruit. If they were store bought frozen I’d just rack on top no pasteurizing. If the where frozen fresh pasteurize them or soak them in vodka. I’m thinking a sour raspberry weissbier would be delicious so I wouldn’t worry to much

5 gallons in my primary, which is why I’m worried about the addition of my raspberries plus additional krausen.

I will be using store bought frozen raspberries.

Not a bad idea to rack some without raspberries! I think I’ll go that route and forego re-racking back into the 6.5gal.


When you rack to secondary. You will have plenty of room for the Raspberries. The trub and beer left behind is going to be about half gallon or more only leaving you 4 or 4.5 gallons in the fermenter. The brix of your Raspberries is not that high and further fermentation is going to barely be noticeably with that little amount. You will not need a lot of headspace.


Me do boil the fruit first. So skin brakes think they call it tawing. Than do add the fruit to secondary. Or our host does sell. Fruit puree. If you do use this buy 2 cans.

I would use the 5gal carboy. First, as many have pointed out, you’ll lose a little racking. Second, 5gal carbons actually hold about 5.5gals. Third, there will not be a big Krause like regular fermentation. In fact, it will likely go so quick you’ll miss it.

Don’t discount using the extract. It’s not fermentable so you may want to dose your beer a little to round out the flavor. The sugars in fruit are fermentable so you end up with what that fruit tastes like without sugar.

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Do not boil the Raspberries you will extract tanning and pectin haze. Take the frozen out of freezer unthaw refreeze and unthaw again. Then crush the Raspberries and rack the beer on top them in the carboy.


Forgive my lack of knowledge, but what is the purpose of thaw-refreeze-thaw? I know that freezing breaks down the walls of the fruit to release the flavor, but I hadn’t heard about thawing and refreezing before the final thaw.

It breaks down the cell walls even more.


I have done multiple raspberry wheat beers. 2.5 pounds to 5 gallons will not even be noticeable to taste in my experience. My best results were with a can of puree from our host and 3-4 more pounds of frozen raspberries that sat in the secondary for a month. I did not boil them first, but I can sure understand why you would. Beer turned out great

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