Cherry Sour Beer

[raymondo]

I've got 20l of a Belgian sour fermenting with WLP665. I planned to make it a cherry sour/kriek type by adding cherry juice.

This morning i juiced 2kg of fresh cherries/morrello mix and ended up with 1.5l of juice. My concern is that the juicer smashed up most of the cherry stones, some small pieces can be seen in the juice - should I be concerned about cyanide content of the juice!

The internet is full of stories about possible poisoning by cherry pips. I know the Belgians let beer sit on a huge amount of cherries for an extended period - I assume there is no problem with that method.

Safe to add juice or not?

Thanks,
Raymondo

 

[strange-steve]

I don't think you need to worry, I'm pretty sure the guy at Cantillon told me they leave the cherries in the cask until they are entirely dissolved, pips and all.

 

[AndysGray]

I would suggest that while the juicer may have taken a few chunks of the outside of the stone, most of the kernels would remain intact - it is the kernels which contain the cyanide. That said, some commercial juicers (macerators) do work by crushing but unless you paid several grand I doubt it would process cherries with stones. I would think it would be easy to check the waste from the juicer and I think you'll find most stones intact - though scuffed. You may also find the juicer is a little blunted.

I found this paper which should give you some re-assurance - the cyanide reacts with sugars to form much safer compounds and the average juice even from a macerator was below 7mg per liter

https://www.arcjournals.org/pdfs/ijfh/v3-i1/1.pdf

Even assuming the worst case you will be adding 1.5l to 20l so dilution to about 0.5 ppm which is below the 2.7 ppm which can cause discomfort.

You should also remember that cyanide is quite reactive so will reduce over time particularly in a fermentation environment.

 

[lancon]

I found by boiling the cherries, (slight amount of water to stop burning until the cherries burst and juice provides liquid) then adding to secondary no problem, stones added but intact

 

[raymondo]

AndysGray / Iancon - thanks for that - will settle down for a detailed read. My juicer destroyed most of the stones and collected the debris along with the waste pulp. A few bits did find their way into the juice. To be honest the Phillips juicer seems to produce a smoothie texture rather than juice.
Anyway, added to bulk fermentation and now bubbling away.
Raymondo