Unfermentable sugars in black raspberries???

[Delaney]

Hi,

I recently designed my first recipe, a raspberry pale ale. I made one part with black raspberries, and one part with red raspberries.

The black raspberry beer is very sweet. The red raspberry beer is not.

The beer was brewed together and separated when racking to secondary.

Is this because there are unfermentable sugars in the black raspberries? I can't think of anything else that would have caused this.

FYI: This beer is F'ing good. The black raspberry is too sweet though.

 

[BigEd]

Is this because there are unfermentable sugars in the black raspberries? I can't think of anything else that would have caused this.

I doubt it. The sugars in fruit are simple ones and very fermentable. Differences in acid content of the red & black, original content of sugars in the berries, yeast and/or fermentation differences are possible contributors to the two end results.

 

[Delaney]

I doubt it. The sugars in fruit are simple ones and very fermentable. Differences in acid content of the red & black, original content of sugars in the berries, yeast and/or fermentation differences are possible contributors to the two end results.

yeast was same as were all fermentation conditions.

 

[erikpete18]

Did you happen to rack to the black raspberries first? If you left your beer in primary for a while so most of the yeast had settled out, you might not have transferred as much over to the first secondary as to the second (assuming a little got stirred up at the very end of the transfer). If the red raspberry secondary had more yeast you might have gotten a much stronger secondary fermentation, while the black raspberries didn't get as much yeast and weren't able to ferment out all of the sugars that the raspberries contributed. Its been a while since I had a black raspberry, but I don't remember them being as tart either. Its possible that the tartness of the reds is covering up a little of the sweetness that the black raspberries aren't able to mask.

 

[Delaney]

Did you happen to rack to the black raspberries first? If you left your beer in primary for a while so most of the yeast had settled out, you might not have transferred as much over to the first secondary as to the second (assuming a little got stirred up at the very end of the transfer). If the red raspberry secondary had more yeast you might have gotten a much stronger secondary fermentation, while the black raspberries didn't get as much yeast and weren't able to ferment out all of the sugars that the raspberries contributed. Its been a while since I had a black raspberry, but I don't remember them being as tart either. Its possible that the tartness of the reds is covering up a little of the sweetness that the black raspberries aren't able to mask.

I racked the exact same amount at the exact same time...

I racked the first 1/3 of beer into a secondary, and added either BR or RR
then I racked the second 1/3 of beer into a secondary, and added the other berries.
Then I racked the final 1/3 of beer into a secondary which berries were not added to.

Perhaps it is simply the tartness. I thought I would share this info with others.

If I were to use Black Raspberries again, I think I'd only use 1-1.5#/5 gallons, whereas with Red Raspberries 3#/5Gallons worked very well.