seeking advice on sulfite dose for pear juice

[Nick]

Hello all, I just finished pressing some very ripe bartlett pears that gave a juice of 1.070 (or slightly above) and a pH of 3.95. 

I need to mix up some more stock solution for sulfite, so the juice is going to have to survive unsulfited tonight.  When I get back to it tomorrow, I am not sure how much sulfite to add.  In the past, I have blended the fruit from this tree with an equal amount of fruit from an early apple tree, and I have treated the resulting juice as if it were simple apple juice, sulfiting somewhere in the range of 25 to 50 ppm. 

This is the first year I plan on fermenting this pear juice by itself.  The high gravity and high pH has me stumped.  Any advice is welcome. 

[Nick]

Replying to my own post here in the hope someone will give me a steer on this question.  I freely admit my own ignorance when it comes to pure-pear musts.  I have read that pear juice has an insatiable need for sulfite, and that citric acid will convert to acetic acid if given the chance.  

Left to my own devices, I will add 50 ppm sulfite, because that was my successful default dose in the years before I acquired a pH meter.  It seems likely this dose will be too low for pure pear juice, and that the sulfite will all be fixed up, leaving none of it free.  (The fixed/free sulfite question: now there's some chemistry I don't fully understand!)

Thanks in advance.

[Lewis]

Nick there's a fair bit already on the site on this topic; I know,  I was reading it v recently. For what its worth, and I'm no expert, for the last 3 years I've made Perry without any acetification problems using 100ppm after pressing and by paying a lot of attention to hygiene and air exclusion, but I'm aware that others recommend up to 110% of the amount required for apple juice at the level appropriate for the juice ph. Some makers of course use none (and I'm guessing accept a level of spoilage to achieve the desired result: too risky for my taste but each to their own)

[Nick]

Thank you Lewis, I also have been searching the archives on this question, but I hadn't come up with any convenient rule of thumb.  It seems there are as many different approaches as there are different cidermakers.  Your suggestion of 100 ppm strikes me as totally reasonable - with the caveat that, with my depth of knowledge on perry making, you could tell me to pour live vinegar into it and I'd be likely to believe you.  Thanks. 

[Andrew Lea]

If you want to be absolutely cast iron safe, then you should go for the 110% SO2 option. But you will have to drop the pH to do that, or you will be over the legal limit and also you won't have anything in reserve for SO2 addition on storage. 

The further you get away from the ideal, the more risk you run. But it's your choice. Some UK perry makers use wild yeast and no SO2 when fermenting, only on storage. Often their perries are detectably acetic but it's all part of the UK style. Since you speak of Bartletts I presume you're not in the UK?  

I don't think anyone can prescribe what you have to do. You have researched it well, you know the variables and the risks, but the final decision is up to you!

Andrew

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[Nick]

I gave this particular must a dose of 100 ppm SO2.  Well below the "cast iron safe" level, but hopefully adequate to hold off the spoilage microbes long enough for an introduced yeast strain to get a foothold.  The pears were quite ripe, but carefully graded to exclude rot. 

Bartlett v. Williams: correct, I'm not in the UK; I'm in the southern Willamette Valley, Oregon. 

Thanks all for your pointers.  

[David Llewellyn]

Andrew, is that “110% of the dose for apples”, e.g. 55ppm instead of 50ppm, or is it “110% more than the dose for apples”, e.g. 105ppm instead of 50ppm?

 

David Llewellyn

Tel: + 353 87 2843879

www.llewellynsorchard.ie

(previously 'fruitandvine.com')

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[Andrew Lea]

On 23/09/2014 21:26, David Llewellyn wrote:
> Andrew, is that “110% _of_ the dose for apples”, e.g. 55ppm instead of
> 50ppm, or is it “110% _more_ than the dose for apples”, e.g. 105ppm
> instead of 50ppm?


Sorry, for convenience I'd just followed Lewis's shorthand phrase ;-)

There never was a strict 110% admonition as far as I know. The old Long
Ashton recommendation, which I have referenced here before I think, is
to sulphite pear juices correctly for the pH as if they were apple, and
then add a further fixed 50 ppm to bind up the higher levels of native
acetaldehyde found in pears compared to apples. This was a rule of thumb
for perry pears in a UK situation. I think it would apply to pears
generally but I don't have the data, and I doubt that anyone does. Like
all recommended SO2 additions, it makes assumptions about the level of
binding components that are present - which are probably rarely if ever
measured.

It is a pity in some ways that when it comes to SO2 additions we are
still working to UK data which was obtained the best part of 50 years
ago and that nobody has recently verified, certainly not outside the UK
AFAIK. It's not actually that difficult to measure gross SO2 binding
parameters from scratch but I bet nobody ever does!

Andrew

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Wittenham Hill Cider Portal
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