Are Cherries Fermentable?

[mtb]

Just dumped a kilo into the FV for a Kriek and am interested to know - is it fermentable, and to what extent? Beersmith considers it a flavour addition so it doesn't factor in increased gravity for it.

 

[Jack of all biers]

It depends on the cherry type. Black cherries have a higher sugar content than red cherries. 1 kg is not that much (guessing a 23L batch?), so I'd expect an increase in ABV of about 0.4%. Actual SG increase is hard to measure due to the variations in cherries from crop to crop or from ripeness etc.

It will take anywhere from 4-8 weeks to ferment out fully, so put it aside.

 

[mtb]

Thanks mate. Red cherries into a 10L batch.. Ultimately ABV isn't too much of a concern, I'm just interested. Will set aside to ferment as suggested

 

[gaijin]

I use this link to calculate the fermentability and ABU additions with different fruit. For example, I used 2.7kg of cherries in my last kriek and it added about .5% of alcohol to my 20L batch. Just enough for the flavour to come through. 3kg is what I usually aim for +/-500g depending on the flavourfulness (is that even a word?) of the fruit.
http://blog.craftbeertraders.com/fruit-gravity-alcohol-calculator/

 

[Lyrebird_Cycles]

If you've got a refractometer just measure the juice. Most fruit juices have about 80-90% of soluble solids as fructose, glucose and sucrose*; sweeter fruit is usually higher than sourer. Juice yield from whole fruit is variable but often around 75%.

Let's assume your cherries measured about 20 brix (cherries go even higher than this BTW). Your kilo of cherries would yield about 750 g juice which in turn has about 150g of soluble solids which in turn would be 120 - 140 g of fermentable sugars which will yield 60 -70g (75 - 85 ml) of ethanol.

As for the effect on ABV, remember that fresh fruit also has a high water content, in this case you are also adding around 600 ml of water.

*Weird factoid: some fruits which soften on ripening do so by breaking down internal starch stores, in which case they can end up with maltose present in the juice. Cherries are apparently one of these but I believe the maltose percentage is very small, ~ 1%

 

[GibboQLD]

Weird factoid: some fruits which soften on ripening do so by breaking down internal starch stores, in which case they can end up with maltose present in the juice. Cherries are apparently one of these but I believe the maltose percentage is very small, ~ 1%

I was working on a fruit/sugar content calculation thing a while ago (and never got around to finishing it), and from the data I collected it seems you're correct about the maltose in cherries. Other fruits with maltose include apricots, guava and raspberries...