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View Full Version : Funky smell, Rudesheimer or spoilage?



zionpsyfer
05-23-2007, 10:41 PM
This one's a little too tough for me to call. One of my batches has started to give off an odor that's progressing from curious to worrisome. The last time I was at my LHBS, one of the employees was gushing about how great his last batch of mead turned out using Wyeast Rudesheimer. Feeling adventurous, I grabbed a bag and went home to begin preparing.


I used my normal sanitation routine, 1 Oz star san in bucket filled 3/4 full, swirl and soak tools. Removed tools and dumped solution out. Dumped 1 gal of hot water in bucket with honey and stirred well, adding refrigerated water to five gallons. Stirred TLS out of it and placed lid/airlock on and waited for must to cool to 72.

After mead was at temp, I pitched the yeast and stirred the heck out of it again.


Ingredients used:
14 lbs Raspberry honey (strong red color, I suspect this *may* have had puree in it)
4 gallons artesian water
1 pack Wyeast 4783 Rudesheimer

OG was 1.094 with the plan being to add pineapple to secondary and backsweeten as needed after the batch stabilized.



The next day it was popping about twice a second, no foam but it bubbled nicely when I stirred it up.. almost making a mustcano. I stirred twice a day for the first three days. The spoon was sanitized every time prior to touching the must. Around day two I noticed a yeast odor, it was a little stronger than any of my prior batches but I wrote it off as a probable characteristic of the rudesheimer.


Over the last few weeks it has continued to grow stronger, taking on a almost sourdough flavor. Today it has a hint of sulphur in the scent. There are no strange growths in there, and I thieved a bit and it doesn't have any off flavors.

Is this something I should expect from this particular yeast? If not, what (if any) actions can I take to nip this possible infection in the bud before it affects flavor? I was thinking perhaps dropping some potassium metabi in.

Thoughts on this course of action? Alternatives?


Cheers, Ray

wayneb
05-23-2007, 10:45 PM
Well, I have no experience with Rudesheimer but I do know that often times the reason that any mead develops "sulpherous" funky smells while the yeast is still active is that the yeast colony is stressed from lack of nutrients (mostly lack of available nitrogen) and under those conditions it starts to produce large quantities of H2S. Maybe that is what is happening in your case. Depending on how far along fermentation has proceeded, it could be too late to add any DAP or other nitrogen source. I suspect that it is too late since you've been fermenting for several weeks now. The good news - free H2S will eventually come out of solution and the sulphur smell will go away. The bad news - some of the H2S can bind with alcohol and make stuff that doesn't come out of solution... leaving you with a permanent "burnt toast" or "rubber" aroma unless you resort to complex and potentially toxic copper sulphate treatments. The key to keeping that H2S from binding with the ethanol in the must and making even nastier stuff that won't go away is to de-gas your must regularly.

The "sourdough" sharpness may be attributable to something else - the presence of raspberry in the honey. Raspberries really have a strong acid combo in their makeup, and after the sugar ferments away that sharpness will be very noticeable in both the aroma and the flavor of any melomel made using raspberries.

zionpsyfer
05-23-2007, 11:49 PM
Thanks for the reply wayneb.

I haven't added nutrients since pitching so it's entirely possible. I'm not quite at the 1/2 sugar break yet, so I'll go ahead and add some tonight. Maybe that and continued daily swirling will fix me.

Thanks again for the advice!

Oskaar
05-24-2007, 02:51 AM
Sorry for not weighing in on this earlier.

If you can get your hands on Fermaid 2133 that should be what you're looking for. The nitrogen source comes from amino nitrogen rather than ammonia. Once you're past the 1/3 sugar break the yeast will look for small doses of amino nitrogen which is what Fermaid 2133 contains. There is no DAP in this nutrient.

Cheers,

Oskaar

wayneb
05-24-2007, 11:10 AM
Oskaar's 100% correct here (as usual!). You don't ever want to add DAP, or nutrient formulations containing DAP, once you've passed the 1/3 sugar break since the yeast are not able to assimilate nitrogen from that source that late in the life cycle. Only the amino nitrogen that essentially comes from dead, autolyzed yeast cells is able to be taken up. So don't just add any old nutrient. I never knew about 2133, so I thank Oskaar again for teaching me something new today!

zionpsyfer
05-24-2007, 08:30 PM
Bah! I've already added 2 tsp DAP, and 1 tsp fermax nutrient (Fermaid K is on my list for the next trip down to the LHBS) Thanks for the info and the explanations though! =)

It looks like I may have lucked out, I just got home from work and there's no longer any sulphur scent and the yeast smell is slight with no sourdough tinge.


Fermaid 2133 added to my shopping list.

My thanks again, I'd probably have ruined / dumped this batch without ever suspecting it was anything related to nutrients.

Oskaar
05-24-2007, 09:43 PM
You might try some gosts or hulls. They'll help to leech off some of the funkadelic smell/taste and provide some small degree of assimible amino nitrogen.

Hope that helps,

Oskaar