Sorbate in Blueberries?

I broke down my 15 gallon batch of mead into 3 five gallon carboys (https://www.homebrewtalk.com/showthread.php?t=39135)...

One carboy is plain mead with a bit of additional honey, the other one is mixed Blueberries and Blackberries, and the final one is mixed Raspberries and Blackberries.

Both of the ones with additional fruit don't seem to be fermenting well at all, especially the blue/blackberry mix. I read that Blueberries contain natural potassium sorbate. Might the raspberries or blackberries as well?

I added additional yeast and yeast energizer but nothing spectacular seems to have happened.

Has anyone else ran into a situation like this?

I make blueberry and blackberry wine all the time, and never noticed an issue. Is it possible that your mead is already at the yeasts alcohol tolerance? Also, you may not see much activity, but that doesn't mean fermentation isn't taking place. Is the sg dropping?

I have a gallon of mead with 12oz of blueberries in it going nuts right now... doubtful. If your mead already was fermenting, the addition of potassium sorbate will only inhibit new yeast growth. The viable yeast still in suspension will remain active.

sirsloop said:

I have a gallon of mead with 12oz of blueberries in it going nuts right now... doubtful. If your mead already was fermenting, the addition of potassium sorbate will only inhibit new yeast growth. The viable yeast still in suspension will remain active.

Click to expand...

YooperBrew said:

I make blueberry and blackberry wine all the time, and never noticed an issue. Is it possible that your mead is already at the yeasts alcohol tolerance? Also, you may not see much activity, but that doesn't mean fermentation isn't taking place. Is the sg dropping?

Click to expand...

Thanks for both of your replies... I put a heater by the carboys and they both kicked off and started to ferment fine!

I have no idea why I had back pressure on the airlock like this.