Frozen Fruit

[edb]

Frozen Fruit

I just picked up a 4lb bag of frozen blueberries, raspberries and marionberries from Costco. I was going to shoot for either a blueberry or raspberry wheat beer but figured I can live with the mixed berries, its got to be better than extract

I've read up on dealing with fresh fruit but with frozen fruit can I assume that they're pasteurized?

Also when adding them I've heard of a couple different ways to use them, in the wort or put them in the primary.

What are the pros and cons of either route, in wort or the fermenter?

If I'm adding them to the wort could I just put them in frozen at the flame out to aid in chilling the wort or do the have to be boiled for a certain time.

Here is a link to the berries
http://tinyurl.com/4nteou

 

[Bob]

There are as many ways to add fruit to a beer as there are brewers. And, like most things homebrewed, opinions are closely-held.

I like to add fruit to the "secondary fermenter" or aging-clarifying vessel. As soon as primary fermentation is over, the green beer is racked onto the fruit.

Using frozen fruit is fine. In fact, I find it good practice to put the fruit through a half-dozen freeze-thaw cycles, adding the fruit after the 6th thaw. This does two things, one practical and the other theoretical. First, the more freeze-thaw cycles you perform, the more cell walls within the fruit will break down, releasing the juices and flavor/aroma compounds into the wort. Second, I've never had an infection from using fruit in this fashion, presumably because the same principle causes the cell walls of potential spoiling microflora to burst.

I don't recommend permitting the fruit to reach a temperature above ~160oF if you want the beer to be clear. Heat will cause the pectins to set, causing a permanent haze.

I also don't recommend putting fruit in the primary. The devolution of carbon dioxide will scrub out most of the volatile flavor and aroma compounds you're trying to keep in the beer, leaving you with purple beer devoid of fruit flavors and aroma.

That's my advice, anyhow. Have fun!

Bob

 

[edb]

Thanks for the great explanation Bob!

One thing I noticed that on the bag it said not to re-freeze the fruit once its thawed, should I ignore and proceed with multi stage thaw/freeze.

I'll shoot for adding them in the secondary, how long should that be? Will the fruit react to the remaining yeast in the secondary?

 

[The Blow Leprechaun]

Bob's information is pretty good.

They probably say not to thaw and refreeze because the initial freezing was probably done extremely quickly to minimize damage to the cell walls (you can accomplish this at home with dry ice), so if you froze them again, they'd break down.

For most purposes, that would be bad. For yours, it's good. So freeze them and thaw them all you like!

 

[cactusgarrett]

I'd suggest racking to a "tertiary" after you get your desired fruit flavor to clear up your beer, then. I've had good results from one cycle of freezing/thawing, so I don't think it's that important to go thru multiple cycles.

 

[Bob]

Cactus, I love your sig.

My experience is that fruit is much more easily assimilated (if that's the right word) after several cycles. It comes out of the bag looking like Oregon tinned fruit purees you can get from your LHBS.

Good one on the "tertiary". Another rack off the mixed lees and fruit pulp will do wonders for clarification. You could fine the beer at that point, too.

Cheers,

Bob