slow fermentation with D-47 yeast

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Sep 14, 2009
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I am making a mead and it is taking a while to ferment. It started at 1.080 and is down to 1.060 today after 10 days. Is D-47 usually that slow with mead? I have added nutrients twice. First when I prepared the must and then again when it had been 6 days and it was only down to 1.070. I have made the same recipe with Champagne yeast and not had any problems (it fermented dry in 8 days) I have started a starter of EC-11118 to pitch if it is still not moving in a couple days.
Seen as how you a re in Cali Im not guessing that cooler temps is the problem! :). A slow ferment is not really a problem just so you know but have you tried energizer? Meads can really use energizer. I have never used that yeast so dont know the tempermentals of it But like I said some yeast ferment fast and some slow and neuther are a good or bad thing. I actually like a slow ferment with Meads and fruit wines as the esters arent burnt off in a vigorous ferment. I say let this go and see the difference in the final product.
I would let it go. At that gravity d47 should take it dry. In my experience d47 can move a bit slow, and temps above 70F will make it real hot. All that said, d47 increases mouthfeel and makes a nice mead. Can you check the pH? That is the most common issue in a traditional.
It's 1.055 today. So I guess I shouldn't worry. It's a 6G batch, how much Fermaid should I add again? Or I could just keep checking every few days. The EC-1118 starter is bubbling away. Maybe I'll take a gallon off and see the difference in the final product. I don't have equipment for checking Ph. I only have an acid test kit.
I use the Lavlin ICV-D47 all the time - i have never had any issues with it. Most of the time it will ferment to dry in about 4-6 days.

Did you any yeast nutrient/energizer?
I have had 2 additions of Fermaid K energizer. Once at the begining and then again 5-6 days later when I got worried about it moving so slowly.
Mead always takes more time to fermment then fruit batches. How much fermaid have you added thus far? Ive had a few meads that fermented for 2 months or more and cae out awesome!
Fermaid-K isn't energiser, it's nutrient......

Energiser is DAP a.k.a. Di-ammonium Phosphate.

This is the kind of thing that drives me up the bloody wall.....

2 nations divided by 1 language.

Nutrient usually contains "some" DAP, but a lot of other stuff as well (that yes, the yeast does need), whereas "Energiser" is basically pure DAP.

If you look over at Gotmead (and have a dig around), there's a calculator to work out how much YANC is needed.

Or you can just check out the Lallemand/Lalvin yeast chart and while it does say that D47 has low nitrogen needs, it also says that it ferments at "moderate" speed.

Either way, if you worked out what the base dosage of DAP should be for the size batch, then you could reduce it by half or even two thirds - so as not to leave/create any possible off flavours.....

Then see if it speeds up a bit.

Oh and fermentation speed can often be relative i.e. how "balanced" the must was when it started - hence the reports/posts of how some people have had a batch go dry in less than a fortnight etc etc!

Dunno if that's any use.......



p.s. YANC = Yeast Assimilible Nitrogen Content
OK. I added 1 tsp of DAP. Another thing that concerns me. Should I move it to secondary and cut off the air space while it takes a while to ferment out?
OK. I added 1 tsp of DAP. Another thing that concerns me. Should I move it to secondary and cut off the air space while it takes a while to ferment out?
It's not entirely necessary, but I usually do. Only because it's hard to reduce headspace in a bucket - plus if you feel you've finished adding nutrients etc then there should be little to no chance of getting a "mead fountain" now. Yes, its fair to say that as it ferments any O2 in the airspace is displaced by the CO2 produced (or used by the yeast of course), but it is a handy additional precaution.........

Oh, and if you suspect that you've used enough nutrient in the batch then the other thing to check would be the pH. Honey can be a total PITA with acidic/pH swings - which I understand is connected to changes in the levels of gluconic acid as the ferment proceeds. I'd suggest that you rack to secondary, then if possible, check the pH (3.5 pH and above would be fine - as you can always add a little acid too taste later). Then just airlock the secondary fermenter - if it still ferments slowly then I'd say just to leave it be - it's heading in the right direction anyway, so it'll probably finish fine (if a little slow).

Give it a fortnight/3 weeks and the see how it's progressing (with hydrometer, not counting bubbles as that's a poor check of ferment progress)


I won best of show with a mead that I had washed my hands of because I thought the taste was a little too harsh. After 3+ years sitting in the carboy, I went to taste it and instantely fell in love...nectar of the gods is exactly what it was. The D-47 yeast that I used did take awhile to take off but it did a great job in the end. I have continually used it in my making and have even gotten it up to 21% by feeding it in my blueberry port.
Stick with it, maybe warm it alittle. If not try and EC-1118 or K1V-116 from lalvin. They shoudn't impart any off flavors unless you let them sit on the lees.

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