Off odor from wine early in fermentation

Monty Knapp · Sep 27, 2018

Started a batch of RJS Super Tuscan (9/19/18). Starting SG: was 1.105. Re-hydrated the yeast this time, but after 48 hours, fermentation had not started. (Maybe over heated the yeast?)
So I just sprinkled another package of yeast over the must (9/21/18). Same yeast - EC-1118.
The next day (9/22/18) I had some yeast activity on the surface.
After another day (9/23/18), I had good foaming started.
The next day (9/24/18) fermentation was strong and the must temperature reached 80⁰F - so I added a 2 liter bottle of ice. This reduced the temperature to 66⁰F in a couple of hours. SG: 1.075.
This may have been the first day I noticed an off smell. The smell is hard to describe. It smells like wine but it's sharp/tangy. Didn't think it was a problem at first.
The next day (9/25/18) temperature reached 76⁰F, so I added a couple of soda bottles of ice - until temperature dropped to 70⁰F. SG: 1.056
On 9/26/18 the temperature was slow to rise. Late that night I added 1 soda bottle of ice when it reached 75⁰F. SG: 1.040.
This morning (9/27/18) temperature is 70⁰F. Today I started wondering about the smell. If I place my nose just off the surface of the must and smell it, it causes an almost burning sensation in my nose. Since I've never done this before, I'm not sure if that normal or not.
Everyday, starting on 9/23/18, I've squeezed the bag of skins and stirred the must. The lid of the primary has just been placed on lose and a towel draped over it. I've been careful to keep everything sanitized.

Is this the acetone odor I've heard about? Is that possible this early in fermentation?

Or am I over reacting?

Johnd · Sep 27, 2018

Monty Knapp said:
Started a batch of RJS Super Tuscan (9/19/18). Starting SG: was 1.105. Re-hydrated the yeast this time, but after 48 hours, fermentation had not started. (Maybe over heated the yeast?)
So I just sprinkled another package of yeast over the must (9/21/18). Same yeast - EC-1118.
The next day (9/22/18) I had some yeast activity on the surface.
After another day (9/23/18), I had good foaming started.
The next day (9/24/18) fermentation was strong and the must temperature reached 80⁰F - so I added a 2 liter bottle of ice. This reduced the temperature to 66⁰F in a couple of hours. SG: 1.075.
This may have been the first day I noticed an off smell. The smell is hard to describe. It smells like wine but it's sharp/tangy. Didn't think it was a problem at first.
The next day (9/25/18) temperature reached 76⁰F, so I added a couple of soda bottles of ice - until temperature dropped to 70⁰F. SG: 1.056
On 9/26/18 the temperature was slow to rise. Late that night I added 1 soda bottle of ice when it reached 75⁰F. SG: 1.040.
This morning (9/27/18) temperature is 70⁰F. Today I started wondering about the smell. If I place my nose just off the surface of the must and smell it, it causes an almost burning sensation in my nose. Since I've never done this before, I'm not sure if that normal or not.
Everyday, starting on 9/23/18, I've squeezed the bag of skins and stirred the must. The lid of the primary has just been placed on lose and a towel draped over it. I've been careful to keep everything sanitized.

Is this the acetone odor I've heard about? Is that possible this early in fermentation?

Or am I over reacting?

First blush, you're probably being a little overly cautious. 80F in a fermenting red must isn't a big deal, but quickly dropping it from 80 to 65 can cause some yeast stress, though it sounds just fine. The burning sensation in your nose when sniffing the surface is probably just CO2, get a big whiff of that and it will make you choke.

Sounds like your first yeast didn't take by the timing, but the second popped in right on time. Fermentation produces all kinds of funky little odors and tastes, don't be overly concerned unless you find something totally overwhelming. Particularly you should be sensitive to the overpowering smell of rotten eggs / sulfur, which indicates the presence of H2S (hydrogen sulfide). It's usually the result of yeast being over stressed due to lack of nutrients and / or temps being too high (80 is not too high). Sounds like the rest of your process is just fine. Carry on!!

Ajmassa · Sep 27, 2018

Just trying to get high off the fumes?

I think your cool. And likely overreacting. Personally I wouldn’t be so concerned over the temps, but you’ve kept it in the 70°s throughout- so kudos to you sir.
Your described the smells well, and to me it sounds like a standard ferment. Although before catching the odors you are smelling, there’s often a couple days of a fantastic smell. It goes from “yeasty” to heavenly overnight. The chemical smells or the sharp tangy odors or however described- I notice coming the 2nd half of my fermentations.
That burning smell is normal too. Taking the lid and towel off and dropping your head to the surface can punch you in the face. But if stirred up well and allowed to breath —that burning smell quickly fades.

Good luck

salcoco · Sep 27, 2018

I would discontinue in the use of the ice bottles and let the fermentation finish. temp rise is not of any concern. lower temp are usually reserved for white wines. If I recall correctly warm temp required to get all of the color from the grapes skins available.

sour_grapes · Sep 27, 2018

Monty Knapp said:
. If I place my nose just off the surface of the must and smell it, it causes an almost burning sensation in my nose.

I agree with the others. In particular, regarding your observation above, my money is on sniffing CO2. This will result in carbonic acid in your sniffer!

Monty Knapp · Sep 27, 2018

Thanks for the feedback.

I've made 10 batches of wine in the last 15 months. Five from kits and 5 Dragon's Blood recipes.
This is the first time the odor has been so sharp and "tangy" - and the first time the yeast failed to start.
The last wine I made was this same kit - RJS Super Tuscan. It turned out very good, but I didn't think there was any oak to it - so I added a spiral for 3 weeks. This caused too much oak - so I resigned myself to a long aging hoping the oak will dissipate - and started this Super Tuscan.

Started thinking that the Super Tuscan was bad luck for me! But maybe not. I started to bottle the first Super Tuscan today, but testing showed the free SO2 was too low. Added some SO2 and will wait awhile and test again. But the good news is that the heavy oak seems to have dissipated already. Didn't expect that. Maybe that's where the free SO2 went.

I got the icing idea from someone on this forum after I posted about a Riesling kit I had that fermented to an SG of 0.995 in 4 days! Temperatures hit ~85⁰F then.
I'll let this one go without ice from now on per feedback. SG is at 1.026 today anyway, so it'll probably be ready for the carboy tomorrow, No ice bottles possible then.

Hope you're right about this new batch. We'll see. Thanks again.