Ultra Fast Fermentation on Merlot Juice Must

[DansWinemaking]

Hi All, I have a question regarding my most recent batch. It's a 2 gallon must in a 3 gallon pail. It's a Merlot from Coloma, 2 quarts of concentrate. I started this wine on 4/21 in the AM. Specs were SG 1.086, PH @3.5, room temp at 70 plus degrees. Added one cup of sugar, grape seeds and oak chips, yeast nutrient and pectic all before taking my readings. I stirred the must daily and it was sizzling pretty good but not enough to blow off the air lock. That was kind of mysterious as I've made many batches in this bucket and expected activity. This morning I opened the bucket and the must was very still, you could see the yeast still barely active if you looked at the must from the side, but it was virtually still. On a lark, I did an SG and the must is at .998. That's almost 12% in 3.5 days? Is it possible for a wine must to virtually complete that quickly? I never saw any heavy boiling, just a consistent activity like an alka seltzer tablet dissolving. Any thoughts? Thanks!

Oh, and I used EC118 yeast for this batch.

 

[cmason1957]

My thoughts. It fermented a little bit fast, but it fermented. Probably time to rack it to a carboy, it might drop a few more points, might not. It's all good.

 

[BigDaveK]

I've had super fast and super slow. It happens. Don't try to figure it out - yeast make the rules and break them on a whim.

 

[DansWinemaking]

Thanks for the feedback. I am going to take it off the Lee's tomorrow into glass. This is an experience for a novice like me, fermented in 3.5 days.

 

[DansWinemaking]

Well, I moved off the Lee's and into glass this morning. Sediment was heavy, despite only 3.5 days of primary fermentation. I'm going to leave this batch alone for a few weeks and check sg again. This was a good lesson that every batch does not follow consistent patterns.

 

[Tripled92]

I've had super fast and super slow. It happens. Don't try to figure it out - yeast make the rules and break them on a whim.

I second this. One of the best cabs we’ve ever done finished in 2.5 days. A lot of people say temperature is the factor but it’s so many other factors as well. That was like our 5th wine and we couldn’t believe it. Now, we realize they all have different timelines.

This is the main reason the digital airlock (if you have ever seen it on Amazon, not the one for like $300 that they use for beer and stuff but it looks like a regular airlock but digital, hard to explain) has so many bad reviews because digital one tries to read it based on the bubbling but just like you said and just like others have noticed, the bubbling rate somehow doesn’t translate to how fast the yeast is eating the sugar.

 

[HMH]

This was a good lesson that every batch does not follow consistent patterns.

Yes and no.

The "yes" part. True, most batches are different, very likely they don't start at the same point and under the same conditions.

The "no"part. Fermentation time can be calculated, based on a low/medium/high temperature range. The formula is TIME (DAYS) = (STARTING BRIX X 0.55)/FERMENTATION RATE. This is assuming adequate and >steady< YAN supply and optimum conditions. The variability is the fermentation rate and that is based on temperature. The 0.55 number is the approximation of the conversion of sugar to ethanol.

The reasons for the inconsistencies are the starting temperature, amount of nutrients in the must (YAN), the type of yeast used, the starting sugar, and pH/acidity. Several other factors that are less critical is/are the clarity of the must, background SO2, and sanitation.

Even though wine yeast have differences, each type is quite predictable to roughly +/- 12 to 24 hours given known (and repetitive) starting conditions.

All the above is based on the laws of chemistry and physics.