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Cwellan
08-29-2010, 10:39 PM
Good evening! I'm having a few problems that I could really use some expert help with - namely sulfur production, and a couple general questions.

Recipe might help:
Yeast: Rehydrated Lalvin D47, pitchhed on 8/21/10 late at night

12 pounds of raspberry honey held at 145F for half an hour

5 gallons spring water

OG 1.084 (was kinda hot, forgot to record exact temp though, 1.084 was the uncorrected. assume temp was roughly 110)

5tsp Fermax fed about a day in, when I noticed lag phase was done
3tsp Fermax fed at 1/3 sugar break (gravity of 1.060)

So, between the lag add and the break add, I noticed a really bad smell of rotten eggs/baby's diaper coming from the carboy. I turned the temperature down over two days from 73 to 66, and between that and the feeding, it definitely helped, but did not completely fix the issue.

Earlier tonight I took a gravity and observed it to be 1.004. Since there was still a pretty strong smell (read - can't smell anything but burnt rubber), I started worrying about mercaptan formation and decided to go ahead and rack it to try to fix the problem. So, racked into a fermenting pail, onto a clean piece of copper pipe, with a lot of splashing, racked back into the carboy after I cleaned it, again with a lot of splashing, and topped off with reserved honey syrup that I'd been keeping in the fridge. This raised gravity to 1.010, filled the carboy up to the neck, and helped with the sulfur smell, but I don't think it completely got rid of it.

Edit: Forgot the general question. I tasted this when I tested gravity and saw it to be 1.020, and thought it was delicious. Is there any way to raise the sweetness on this back up to that level without using sulfites and sorbate, and not get a basement covered in shards of glass and mead?

Advice? Thanks in advance for replies.

akueck
08-30-2010, 12:56 AM
I'm not one of the resident sulfur experts, so I'll defer that question for later.

As for the sweetness level, first I'd say don't try to hit a particular gravity for sweetness especially when the mead isn't done yet. The flavor will go through a lot of changes over the next few months, and you might find it doesn't need to be sweetened, or needs less than you think. Delay sweetening it as long as you can stand it. When you do sweeten, do it to taste rather than trying to hit a particular SG.

Sweetening the mead without stabilizing it somehow is asking for trouble. Chemical treatment is only one way to stabilize, you can also use sterile filtration or lots and lots of time (several years). Using plastic soda bottles and/or keeping the mead really really cold (30F or so) can minimize the risk of flying shrapnel, but with obvious downsides.

fatbloke
08-30-2010, 04:54 AM
Good evening! I'm having a few problems that I could really use some expert help with - namely sulfur production, and a couple general questions.

Recipe might help:
Yeast: Rehydrated Lalvin D47, pitchhed on 8/21/10 late at night

12 pounds of raspberry honey held at 145F for half an hour

5 gallons spring water

OG 1.084 (was kinda hot, forgot to record exact temp though, 1.084 was the uncorrected. assume temp was roughly 110)

5tsp Fermax fed about a day in, when I noticed lag phase was done
3tsp Fermax fed at 1/3 sugar break (gravity of 1.060)

So, between the lag add and the break add, I noticed a really bad smell of rotten eggs/baby's diaper coming from the carboy. I turned the temperature down over two days from 73 to 66, and between that and the feeding, it definitely helped, but did not completely fix the issue.

Earlier tonight I took a gravity and observed it to be 1.004. Since there was still a pretty strong smell (read - can't smell anything but burnt rubber), I started worrying about mercaptan formation and decided to go ahead and rack it to try to fix the problem. So, racked into a fermenting pail, onto a clean piece of copper pipe, with a lot of splashing, racked back into the carboy after I cleaned it, again with a lot of splashing, and topped off with reserved honey syrup that I'd been keeping in the fridge. This raised gravity to 1.010, filled the carboy up to the neck, and helped with the sulfur smell, but I don't think it completely got rid of it.

Edit: Forgot the general question. I tasted this when I tested gravity and saw it to be 1.020, and thought it was delicious. Is there any way to raise the sweetness on this back up to that level without using sulfites and sorbate, and not get a basement covered in shards of glass and mead?

Advice? Thanks in advance for replies.
Excluding the sulphurous issue, one of your problems with setting the level of sweetness this early is knowing what the starting gravity was accurately.

From memory, I recall that D47 has a tolerance of about 14% - so if the gravity was in fact 1.110 then the yeast is gonna be pretty much finished to max listed tolerance as 1.110 has potential for about 14.5% ABV - but if it was closer to 1.084 then you're thinking of a possible 11.5% ABV so that the yeast still has some viability to start re-fermenting (bottle bombs etc......)

I'm thinking that without the use of sulphites and sorbate, you would either add a little more honey and see if that starts re-fermentation, or you could "cold crash" it (if you're happy with the flavour so far) in the fridge and then start the racking process.

The problem with cold crashing to reduce/remove the yeast is that once you've got it clear, any honey/sweetener you add (if it's fermentable) might still restart the fermenting - as unless you sterile filtered it, there'd still be some yeast cells present (of course, you could always try bottling it in champagne/sparkling wine bottles and use the correct stoppers and wire cages - though I still suspect that you'd have to keep them somewhere appropriately safe just in case they started up again)

That's my read of the situation anyway.

Oh and the lallemand yeast chart shows that D47 has low nitrogen/nutrient needs and would normally ferment to 14% - so I don't know about how to sort any sulphur smell you might still have or get - normally you'd add nutrients (DAP etc) and stir the hell out of it........

regards

fatbloke

Medsen Fey
08-30-2010, 09:18 AM
Welcome to GotMead Cwellan!

It is frustrating to have a stinky batch, and I am a little surprised because D47 usually behaves, especially since you did give in nutrients. I'm not quite certain, but I believe Fermax has less autolyzed yeast than Fermaid K, and that may mean that it does not provide as many of the trace nutrients needed to prevent H2S production. The amount of nutrient provided was a bit light (perhaps 110 ppm nitrogen), and next time, using some DAP in addition to Fermax may be appropriate. Even so, it is unusual for D47 to get so stinky.

First thing to do is refrain from using copper until the fermentation is finished. Active yeast will respond to copper in their environment by producing more hydrogen sulfide. If your batch is still stinky now, I'd treat it with a big dose of yeast hulls - 2 grams per gallon.

If it is still smelling when fermentation is complete, I'd rack it and then treat it with copper. There are other alternatives that can be used including Kieselsol fining, and reintroduction of aerated lees, but I think I would just try the copper. If any odor persists, I'd treat with ascorbic acid 25 ppm and then retry the copper after another week or two.

Cwellan
08-30-2010, 08:09 PM
Thanks Medsen, that's exactly what I was looking for. I think one reason it may have gotten so stinky was it got a little too excited. Initial fermentation temp was 73 and it only took a week to go down to 1.004.

As far as yeast hulls - haven't seen just yeast hulls at the LHBS, but there is yeast energizer which has a lot less white salt crystals than Fermax. Since it looks like mostly yeast, is that acceptable to use? Or would it be better to cook 10 grams of yeast to kill them, then throw that in?

Thanks again!

PS In regard to the setting sweetness, that was more of a changing goal thing. I initially designed this to go completely dry so it could be oaked for a few months after it cleared, and then forgotten about for 3 years, it just tasted so good at 1.020 that I wanted to change my mind. I suppose a better route would probably just be brew up another batch than to try to change this one now that it's been launched.

Medsen Fey
08-30-2010, 08:27 PM
As far as yeast hulls - haven't seen just yeast hulls at the LHBS, but there is yeast energizer which has a lot less white salt crystals than Fermax. Since it looks like mostly yeast, is that acceptable to use? Or would it be better to cook 10 grams of yeast to kill them, then throw that in?
It is too late for the energizer at this point, and while you can boil yeast and use them, my preference would be to buy some real yeast hulls so that I wouldn't be adding nutrients for spoilage organisms.




..., it just tasted so good at 1.020 that I wanted to change my mind. I suppose a better route would probably just be brew up another batch than to try to change this one now that it's been launched.

Actually we often recommend fermenting batches dry, and then stabilizing them with sorbate/sulfite so that you can sweeten them up to the taste that suits you best.