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I crushed and pressed my own pears this year hoping to make a perry. Did allowing the pears to become very soft prior to pressing change the sugars to become more fermentable?
I crushed and pressed my own pears this year hoping to make a
perry. The original specific gravity (SG) was only 1.034 so I added 5
pounds (2.3 kg) of sugar, some British ale yeast and yeast energizer. It
fermented for a bit, then stopped at about 1.025 and tastes very sweet.
I then added a white wine yeast, but it still did not ferment. I also
made a batch with both apples and pears and added 5 pounds (2.3 kg) of
sugar. Like the perry, it fermented then stopped short and is sweet. I
suspect the pears have non-fermentable sugars. Is there anything I can
do to encourage further fermentation, or should I learn to enjoy sweet
wines? One more note, we made a batch of perry from the same pear tree
two years ago and it was delicious and dry. We let those pears soften
much longer than the ones we used this year. Did allowing the pears to
become very soft prior to pressing change the sugars to become more
You are making me thirsty! I am a huge fan of cider and perry (pear
cider), especially when it's tart, dry-ish and has a sparkling finish.
Yummy yum yum! I applaud you for keeping this ancient and tasty art
alive in your neck of the woods.
You present an interesting scenario above. Since I don't know your batch
sizes (volume) I can't help you calculate what 5 pounds (2.3 kg) of dry
sugar (cane sugar? Malt sugar?) would do to your specific gravity,
though an initial specific gravity of 1.034, being about
8.5 °Brix, certainly needs some sugar added to it. It's possible you
added too much, which would account for your stuck fermentation of about
6.5 °Brix or so (the 1.025 that you mention above). Once alcohol levels
get above 14.5%, most yeasts start to struggle to complete a
fermentation, which is why I try to never start my fermentations above
25.0 °Brix (1.106 specific gravity) if I can help it. Though the number
varies from year to year and winery to winery, in my experience, alcohol
conversion rates tend to be 0.55–0.58 alcohol points for every degree
of Brix you start with. I recommend making sure you don't add too much
sugar; be sure to measure your initial starting Brix and add sugar
gradually to your must to avoid over doing it.
I'm no pomologist (fruit scientist), but from what I understand, letting
pears soften (i.e. get ripe) prior to pressing doesn't make the sugars
more fermentable per se, it just makes more sugar. Soft, ripe fruit has
a higher sugar concentration than hard, unripe fruit due to ethelyne
gas triggering enzymatic activity, which transforms starches into
sugars. My guess is that you experienced something this year that lead
to both the stuck fermentations you witnessed.
Though the causes of stuck fermentations are sometimes difficult to
deduce (I myself was stumped by one of my own this year — arrrgh!), here
are some possibilities: you added too much sugar to your batches (and 5
lbs/2.23 kg of sugar could go a long way depending on your batch size),
you had a bad batch of yeast that wasn't robust enough to finish the
fermentation, you had an organism get into your fermentations (either
acetobacter or pediococcus) that caused the VA to climb and the yeast to
give up, or you didn't have enough of a certain kind of micronutrient.
The latter reason is particularly interesting because fermentations
conducted with high levels of dry sugar (beet, cane, etc) often don't
have the required nutrients or healthy fermentation factors your average
yeast beastie requires. Perhaps the year you started with riper fruit,
your yeast enjoyed the goodies (amino acids, pantothenate, biotin,
vitamins, nitrogen, not to mention suspended solids/pulp that are often
important for fermentation kinetics) that come with fermenting real
fruit juice rather than a white sugar solution. Pure sugar adds degrees
Brix to a fermentation (higher potential alcohol), but little else
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