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View Full Version : Rancid/Rotten Smell Metheglin



clouviere
06-24-2007, 06:38 PM
Hey guys...I need a little help with some trouble shooting. I made 3 batches in early May. All from the same honey, with the express purpose of trying the same recipe with different yeast. And two of the three have gotten a really nasty rancid or burnt plastic smell along with a nice milky white substance clinging to the top of the mead and sliding down the inside of the carboy. Batch 1 has exhibited no smell or milky substance yet, batch 2 has the smell in the back ground and batch 3 was so bad with the smell that you couldn't put your nose to it (I actually tossed it it freaked me out so bad).

On to the particulars.

I used the same recipe for each batch with a different yeast in each:
16# honey and distilled water to 5 gallons.
1/2 a finger of ginger
2 sticks of cinnamon
1/4 tsp. rosemary
1/2 tsp nutmeg
1.5 vanilla beans

3 tsp of yeast nutrient
1 tsp acid blend
1 tsp gelatin

The process was very similar for each batch. I put a gallon of water in the bot, got it up to a boil then lowered the heat and folded in the honey making sure to keep the heat around 150 for a few minutes than I killed the heat (I know...I have since read that there is no need to use this method and plan to do it like Ken and Okaar suggest with my next batches). I then put my must in the fridge until the temp got down below 100 then poured it into a 6 gal carboy with a couple gallons of cold dist. water already in it. Then I filled to 5 gallons and did my best to manually mix the must with the water. Not sure if I did a good job or not though.

I then pitched the yeast. Batch 1 I put in Wyeast Sweet Mead 4184 which is a liquid yeast. Batch 2 I used their Dry Yeast, and batch 3 I used Lavalin D-47. I rehydrated the D-47 with some of the must (which was probably the wrong thing to do...I now know).

Initial gravities were the same 1.114-.115. I then let them ferment. Once the activity feel below 1 bubble every couple minutes I racked them off. There was no off odor or taste in batch 1 or 2 at this time but batch 3 was so bad you couldn't put your nose to it with out recoiling from it. Like I said it had a distinct milky substance that was on the surface of the mead and it was think and slid down the carboy as the liquid was racked off.

I racked off batch 1 the other day, and other than having a gravity of about 1.060 and being a little sweeter than I expected it was fine. Smelled nice and tasted nice. I just racked off batch 2 today (almost a month since I did it the last time) and it has the same oder and taste as batch 3, but it is in the back ground. It has a gravity of 1.002 and is pretty dry and has about 14% alc, but it has that odor and tast.

The best way I can describe it is that it smells like organic stuff in the trash can that has sat too long before being taken out. Batch 3 was so bad I just threw it out. Batch 2 it is there...but in the back ground.

The only things I can think of is either I didn't clean as well as I thought I did, my air lock wasn't as tight as I thought, or my ginger being cut on and then reused a couple days later opened up the door. I made batch 1 on may 8, batch 2 on may 10, and batch 3 on May 13...and used the same piece of ginger for all three.

Any ideas would be helpful...as I would like to know what I did wrong so I don't do it again. >:(

Thanks in advance.

Chris

Johnnybladers
06-28-2007, 08:58 PM
Might the white milky substance have been the gelatin (don't recall having seen that in a recipe before)? Hopefully someone better able to help will chime in as I'm just taking a guess.

teljkon
07-02-2007, 01:01 AM
weird id look some place for common spoiling bacteria I remember reading about all the different bacteria that can destroy your batch and there may be some answer there for you. Personally I would place my bet on the ginger but I donít know how you added that to your batch so I canít give you a definite. It seems to convenient that each batch had more of this smell and flavor right in order. It could be mouth fungus from racking if you use the suck method?? The funny thing is if you donít get ill from it you could pass of that smell nad taste of as grenache juice that you added in on perpus :tongue3:.

Leonora
07-02-2007, 02:04 AM
Greetings,

I am sorry to hear of your troubles.

I am quite comfortable with stating that none of the spices would be the cause of your mead's foul odor. Spices are antifungal and anticeptic and are frequently used in traditional cuisine for those reasons. I very much doubt that the ginger is your problem for this reason.

I have never seen a recipe use gelatin in the primary, so I am guessing that is the cause of your problem. It is sometimes used very late in the fermenting process to help the clearing process, but most folks use other things like Sparkaloid. I am assuming you used something like Knox Unflavored Gelatin.

I would avoid using the acid blend until the end of fermentation. Mead is more likely to go acidic during fermentation so adding acid up front just increases the stress on the yeast. If needed, add to taste. I would also not use the geletin. Did you add all the neutrient at once? There is a lot of information around about how to feed the yeast in several stages. (It might be in the Patron section, but you can try to search on NAS) Some types of yeast food can leave a strong taste in the mead if you add too much.

And I'd revisit my sanitation procedures. You don't mention how you sanitize so I wonder if you grew something on a piece of equipment over time.

My one other thought is that stressed yeast can throw off some pretty funky smells/tastes. I just had some mead a new brewer made and it has a distinct phenolic smell/taste due to poor early day management of the yeast (not enough feeding or O2 in the first week).

Do you have a LHBS where you can take a sample in? It's pretty hard to figure out things like this with just word descriptions.

Good luck,
Leonora

Oskaar
07-02-2007, 02:55 AM
As mentioned by Leonora below. Your problem isn't with the ingredients (but gelatin in the primary is not something I'd recommend) but with yeast stress.

Typical smells from yeast stress are derived from production of H2S and SO2. Your beasties were begging for nutrient.

Cheers,

Oskaar

teljkon
07-02-2007, 03:14 AM
I still wouldnt throw out ginger as a possible source of the problem ive definatley had ginger go rancid. It tends to grow a white fungus, ive spent more than a few minuts triming it away before making my home made salad dressing.
:cheers:

Oskaar
07-02-2007, 03:53 AM
Yes, Teljkon anything is possible and the ginger may be the culprit, but there are several other additions as well that could be too. So I don't think this is an issue of ingredient contamination as much as it is an issue of must deficiencies and acid additions that made it a very harsh environment for the yeast.

Considering the ingredients in this batch yeast stress is the most likely candidate (it may be that the stressed fermenation also triggered some of the less desireable compounds in the gelatin as well as Leonora mentioned and makes sense).

1. Distilled water - No minerals to help the initial fermentation
2. Boiled distilled water - No minerals or O2 to help the initial fermentation
3. No aeration or supplemental nutrient additions post lag phase and 1/3 sugar break
4. Rehydration of Dry yeast with acidic, unoxygenated must
5. PABV of each batch if fermentation has run to completion is 15.4% which is plenty high to inhibit most spoilage organisms and kill off the yeast used in the fermentation.
6. As Leonora mentioned the spices mentioned in his recipe are inherently microbial inhibitors. This doesn't mean that they couldn't have caused the problem, just that in aggregate they make it that much tougher for an infection to gain a foothold, especially when coupled with the high ABV of 15%
7. Up front acid additions in mead are pretty much asking for problems if one has not undertaken to measure the pH prior to the addition.
8. Ginger used over a few days certainly could be a contributing factor. I think more likely that any infection is due to the sanitization (or lack thereof) in preparing, handling and additions to the must.
9. I've smelled some pretty foul stuff with gelatin in it and that could also be a contributing factor considering the source of gelatin.

My .02,

Cheers,

Oskaar

teljkon
07-02-2007, 11:58 PM
Therese a little story id like to relate that I read about a brew pub in the midwest where the brewer suddenly lost head retention (the nice foam at the top) in his beer. He looked every where for the problem changed his recipes checked sterilization added this adjunct and that. A turn out the problem was a new soap his bar manager was using on his glasses. The moral of the story to me is donít rule out any factor when youíre having a problem. Fermentation is wonderfully complex thing. While you have years of experience on me and do know better where to look first Oskaar. Clouviere should run down your suggestions first it is always good idea to pay due diligence to all factors.

:happy10:

PS. Is there a scientific reason that I donít know about that a fungus wouldnít separate from the must and float at the top. Id think that this is especially possible with the dead cells left behind after the alcohol killed them.

:confused4:

Oskaar
07-03-2007, 05:10 AM
Hi Teljkon,

I totally agree not to rule anything out. I run down my list of most likely suspects and eliminate them as causes and then proceed to the stuff that is less likely to me to be the culprit. Just my own methodology that I follow every time and that way I don't miss anything.

As far as the fungus floating to the surface. I suppose it could, but I don't think it would proliferate there once exposed below the surface to CO2, ETOH toxicity, and lack of oxygen (say in Aspergillus sp.) would pretty much spell doom for many molds, but I'm sure there are some that could survive. Like I said below, it could be the ginger, but I think it's more likely a combination of yeast stress, gelatin and sanitization issues. Also, sensory profile of molds would be more musty, powdery, earthy dank and acrid than what our guy below was describing.

Hope that helps,

Oskaar