Ferment question

[SLM]

50 gallons cab sauv fermented slow and steady in a 66 degree room. After 2 weeks, at 1.004 I pressed into 7 caboys of various sizes, expecting ferment to finish in carboys. 4 carboys of free run with heavy lees are chugging away. 3 carboys of pressed wine, lighter on the lees, are showing no activity. What's going on?

 

[mainshipfred]

50 gallons cab sauv fermented slow and steady in a 66 degree room. After 2 weeks, at 1.004 I pressed into 7 caboys of various sizes, expecting ferment to finish in carboys. 4 carboys of free run with heavy lees are chugging away. 3 carboys of pressed wine, lighter on the lees, are showing no activity. What's going on?

Nothing they will start, the yeast just got stunned a little. I bet they will be perking away tomorrow.

 

[SLM]

Hmm, so nothing to do with the lees? Just the act of squeezing the grapes shocks the yeast? I'm hoping to rack off gross lees tomorrow as I won't have time during the week. So it should keep chugging till it's done?

 

[mainshipfred]

Hmm, so nothing to do with the lees? Just the act of squeezing the grapes shocks the yeast? I'm hoping to rack off gross lees tomorrow as I won't have time during the week. So it should keep chugging till it's done?

I believe so, it happens to me on occasion and I can never figure out what I did different those times.

 

[CDrew]

I have seen this too, and what I think happens, is that pressing "de-gasses" the new wine. So any visible fermentation (air lock bubbling) will happen only after enough CO2 is made to saturate the solution and then it starts coming off. So your yeast in the pressed juice is likely working away just fine, and you will start to see bubbles once they have re-saturated the solution with CO2. If it's really 66F they are working slow anyway. Warm them up just a bit if it's bothering you.

 

[winemaker81]

Warm them up just a bit if it's bothering you.

That's my thought -- kick the temperature up to 70-72 F and the wine will likely start perking. Although IMO Mother Nature has an odd sense of humor.

My 2019 second run fermented to 1.000 -- I had 2 batches, lightly pressed and hard pressed. Both stopped at the same SG and didn't move. I added a bit of nutrient and more yeast. No change. I put the light pressed in a barrel in mid-December and the hard pressed stayed in a carboy. At the end of February, both were still at 1.000.

At the time the wines stuck, the temperature in the cellar was upper 60's and there were no sharp temperature swings.

Fast forward to the end of March -- the bung on the barrel blew 3 days in a row. I checked the SG in both the barrel and the carboy -- both were at 0.992. The fermentation re-ignited in both at roughly the same time. I didn't think about it at the time but this may have coincided with the temperature in my cellar rising from 58 F to low 60's F.

Or maybe Mother Nature was simply amusing herself.

 

[Rice_Guy]

For seeing bubbles with an air lock there needs to be excess gas pressure in solution. ,, The act of racking and pressing lowered the ppm of dissolved gas so that it balanced with atmospheric pressure and temperature. ,, no the lees are not important, ,, yes squeezing/ introducing oxygen encourages yeast growth. ,, as Drew said temperature could speed it up. ,, at 1.004 you will have entered a phase where the yeast metabolism has started to slow and viable cell count is decreasing and the quantity of gas produced decreases. > patience

Hmm, so nothing to do with the lees? Just the act of squeezing the grapes shocks the yeast? I'm hoping to rack off gross lees tomorrow as I won't have time during the week. So it should keep chugging till it's done?

 

[SLM]

You were all right. It took a couple days but it's moving now.