Stumped with zero fermentation, not just stuck

Help! I'm seeing zero fermentation from a 6-gal batch of cider. using fresh apple juice from a local mill and blend of apples. The juice has no additives and hasn't been heated, UV'd etc.

After sulfiting to 100 ppm and adding a little pectinase, I waited a coupled days then pitched WLP611 New Nordic Ale Yeast, which I haven't tried before, and a little yeast nutrient, and shook it up to get some O2 in the mix.

After a week, nothing was happening so I checked the SG and it was 1.055, same as when it started. So thinking the yeast went bad somehow, I re-racked it and pitched with a dry packet of Cider House Select. A week later absolutely nothing happening. Without re-racking it, I pitched Fermentis SafCider, rehydrated according to mfg tech sheet. A couple days later, still nothing happening. It's in my semi-underground garage with a steady temp of 61 deg F, using containers cleaned with StarSan as usual. Juice ph 3.5. I've made numerous batches of kombucha and cider and have never seen this problem. It's not that fermentation has stuck - it never got started.

Any suggestions, ideas welcome. Thanks, Tom

 

That's double what's recommended*, clearly the source of the problem.

You need to aerate thoroughly, aerate some more, and then aerate again. Aerate one or two more times and then pitch some more yeast.
Properly rehydrate dry yeast.

Welcome to HBT!

*If you want zero wild microbe activity, aim for 1ppm molecular SO2. If a little wild character is OK, aim for 0.5ppm molecular SO2 or less. The amount depends on pH. Here's a good sulfite calculator:
http://fermcalc.com/FermCalcJS.html

 

Claude Jolicoeur recommends 100 ppm based on a ph of 3.5, on page 213 of his book "The New Cider Maker's Handbook."

 

That is an error stemming from Lea's (his source) mixup of total vs free SO2.

50ppm free SO2 provides 1ppm molecular SO2 at pH 3.5.

 

Ouch...that's a significant error. I looked all over his web site and don't see a correction posted...will drop him a note. thanks, Tom

 

If you do, please report back. This isn't the first time we've seen issues with sulfite levels. Lea and Jolicoeur are the most respected cider masters of our time, it'd be reassuring to know if these guys have made an error and intend to correct their published data.

 

Here's Jolicoeur's graph citing Lea:

It's an ambiguous interpretation of...

Lea's more detailed graph:


Lea's graph shows explicitly that at pH 3.5, 50ppm free SO2 is needed to achieve 1ppm molecular SO2. Total SO2 needed is 100ppm.
Everything is good so far.

The mixup occurs here when Lea converts to Campden tablets:


Using pH 3.5 as an example, Lea suggests 2 Campden tablets.

On the same page, Lea says "Campden tablets [...] are formulated so one tablet [...] per [Imperial] gallon gives 50 ppm"
This is a pretty ambiguous statement.
The truth is that each tablet give 50ppm free SO2, from ~100ppm total SO2 (rounding for simplicity).

It seems clear that Lea used free SO2 to hit a target of total SO2, thus effectively doubling the amount.
In truth, 2 Campden tablets at pH 3.5 give ~200ppm total SO2 (100ppm free SO2) per Imperial gallon, about 2ppm molecular SO2.
That's where you run into problems.

Everyone I've seen add 2ppm molecular SO2 had trouble stating fermentation.

Hope this makes sense.

FYI: An Imperial gallon is larger than a US gallon. Campden tablets add about 65ppm free SO2 per US gallon.

FYI: Not all Campden tablets are the same. Some are potassium and some are sodium, which are not interchangeable.

 

Got fermentation going by letting the pitched apple juice warm up to about 68F. Let it cool back down to 60F and it's still going well. It may be that excess sulfite delayed things a bit but it doesn't appear to be a critical problem.

 

I was looking at this again, and apparently I misunderstood what he was saying. There was nothing wrong with the conversion; he's genuinely recommending to use that much sulfite.

There's no obvious explanation why those recommendations are about twice as much as what seems appropriate empirically.

I've experimented myself and I know that when ignoring sulfite binding entirely, the calculated 1ppm molecular sulfite addition is enough to keep wild microbes at bay for several weeks at room temperature (65-75°F), even without any pitched yeast to inhibit the wild stuff. To me, that clearly demonstrates the level I'm using is effective.
This non-binding-corrected sulfite level (40% of Lea's recommended level) also seems to start to cause hydrogen sulfide problems with pitched yeast. To me that says even the lower level I'm using still may be a little too high.

There's absolutely no other detailed information published online about pre-fermentation sulfite that I can find. I'm not sure whether I just don't have the right books/publications or whether we're still in the sulfite dark ages.
It's hard to trust Lea's work at this point when everything empirical I see points to it being inaccurate and I can't find corroboration from any other sources, especially in vivo, practical data.

Sorry if that sounds like a rant. It bothers me sulfite has been used for thousands of years and information is so scarce and conflicting.

 

Thanks for sticking with this. I would dearly like to take Lea / Jolicoeur's recommendations as gospel, considering their status in the cider community. But we've had people report here difficulty in getting fermentations to start after using their numbers, and other published data contradicts them. I just bought my first SO2 test kit, and I'm not sure what I'm looking for now.

 

There are two main unanswered questions that I have.

I'd like someone to confirm the binding level of SO2 by testing free SO2 minutes after adding some KMS to fresh must. I believe the testing method matters since some can read falsely high by converting some of the bound to unbound (?).
Lea suggests 60% binding and I haven't see any other primary literature reporting binding level.

Next (and more difficult) I'd like someone to confirm the actual validity of the target pre-fermentation molecular SO2 levels. How much apparent free sulfite is needed to fully inhibit wild microbes and how much to partly inhibit wild microbes (i.e. allow some activity from wild yeast like Kluveromyces and Brett)? What level starts to inhibit pitched Sacc?
This is obviously what actually matters -- empirical data in vivo.

 

I found a couple articles that really helped me understand the issues. These are wine references but cider is similar to white wine.

From Cornell:
https://grapesandwine.cals.cornell.edu/newsletters/appellation-cornell/2012-newsletters/issue-12/article-contains-sulfites/
https://grapesandwine.cals.cornell.edu/newsletters/appellation-cornell/2016-newsletters/issue-25-may-2016/grapes-101/
and from Wyeast https://www.wyeastlab.com/sulfurdioxideadditions/

Jolicouer is confusing because his chart on p. 213 should be labeled "Total ppm SO2" but it is not, and some of his details are a little vague.

There is a new-ish SO2 test methodology available, I'm going to order some of the gas detection tubes and give it a try to some fresh must after adding KMS, just as you suggest.
https://grapesandwine.cals.cornell....ll.edu/files/shared/Research Focus 2015-4.pdf

 

Those are good articles but neither touches on my unanswered questions (how much pre-fermentation free/molecular do we need and how much total is needed to get that).

Wyeast suggests adding 50-80ppm (what I assume is total) SO2 at crushing, which is more on par with what I'd recommend based on experience and see suggested by other more experienced wine makers.
However Wyeast doesn't even bother to adjust for pH and don't list any references or supporting data.

Please let us know what you can determine with testing