Fermentation Start Problem

First things first, Sandi. I know that many TJ's products do not contain preservatives or stabilizers, but are you absolutely sure that both the cider and the cherry juice are preservative-free? Re-read all the fine print on the labels of those containers; if you have sorbates, benzoates, preservatives or stabilizers other than ascorbic acid listed, you may have a problem. Make sure that the dried cherries are also free of preservatives.

If that's not the issue, then with all the acid sources in there, I'd next be worried about pH. Do you have a way to check the pH of the must?

Next in line -- rehydration water temperature. You used warm water; do you know for sure that it was at or below 105F? Water at that temperature is felt by most people to be just slightly hotter than room temp - and it is about the hottest that a hot tub ever gets. Any hotter than that, and your yeast may have expired.

Next -- what was the temperature of the must? In the 20 mins that yoou waited for the yeast to rehydrate (that's not a problem, BTW -- you can go up to 30 mins before the yeast are starved for energy sources), the rehydration temperature probably dropped down to the mid 80's F. If your must temp was below about 70-75, then you may have thermal shocked the yeast at pitching. Ideally you want the temperature of the must to be no more than 10 degrees different from that of your rehydrated yeast. Yeast that have been thermally shocked will sometimes start to ferment after a very long lag interval, but it is a good idea to re-pitch to ensure that you have a healthy colony in there, in the event that thermal shock did occur.

Finally -- you may have already solved the problem. Musts that are too cold will not ferment well. D47 works down to about 18C; that's 64F, and your must may have just been too cold overnight. The space heater should get things started, if that was the problem. Do you have a thermometer that you can use to check actual must temperature?

D47 will start in high gravity musts, but you have to nourish it carefully, and keep the temps within the yeasts' sweet spot, for it to work.

Hope these suggestions help!

Four ideas here.

1) Maybe your gravity is too high. That gives you 18.8% ABV if it were to go to dry. That just might be too much negative osmotic pressure on the cell wall for this yeast. They are esentially trying to not dehydrate themselves. Might want to dilute down with water to SG of 1.130?

2) Too much acid. Everything you have mentioned is acidic, did you take a pH reading?

3) Temperature difference between the rehydration solution and the must? I have read that 10 degrees can cause the yeast to go dormant.

4) Forgot the step in rehydrating where you add must to the rehydrating solution? This helps ease the yeast into the must, both temperature and osmotic pressure. Thanks to Oskaar for finding this for me. Page 16 is the one you are after.

Edit: WayneB beat me to this.

Sandi,

It could be either the cold shock when you pitched, or an overall cold must temperature, or both. But since you have another pack of D47 readily at hand, it won't hurt to rehydrate, attemperate, and pitch that in. It's pretty cheap insurance to maximize the chances that you'll get a healthy fermentation overall.

You're welcome!

Also remember that airlock activity isn't the sure sign of fermentation that many think it is. If you are using a bucket for primary, especially if the rate of fermentation is slow, there may be enough leaks in the bucket seal to allow CO2 to escape without ever bubbling out the airlock. Trust your senses -- you'll see evidence of a slightly effervescent "fizz" on the surface of a must that is fermenting in primary, and you should be able to hear it as well. Ultimately, seeing a change in SG over the course of a few days is the surest sign that fermentation is taking place.

I have a bucket lid that you have to basically ruin a stopper to get it to seal the hole. I had to press it in there that hard to get it to be sealed in order to get the airlock working. FWIW.

The saving grace is that when you're early in primary the fermentation is vigorous enough to produce a blanket of CO2 over the must without any cover at all. No airlock is really needed. In fact no hard cover is needed -- just sanitize a tightly woven cloth (a piece of an old bedsheet works well, or an old dish towel), cover your bucket with that, and secure it in place with a bungee cord. Better than any airlock or blowoff tube arrangement that I've ever seen, since there's never a chance of plugging a lock or a blowoff tube because the CO2 vents through the fabric over a large area. The fabric's just there to keep airborne nasties from falling into the must -- and from my experience, it does that job perfectly.

With the fast primary fermentation that I get now that I employ Go-Ferm rehydration and staggered nutrient additions, I have most of my primary fermentations complete in a week to 10 days. So I don't even bother with a hard cover on the bucket at any time, for most of them. Only the really high gravity musts take long enough in primary (2-3 weeks at most) that I feel the need to use a hard cover -- and that's only after the first 10 days with a ragtop have passed.