To Stir or Not to Stir - Juice Buckets

[pete1325]

Just curious to know how many stir during primary fermentation and if so how often?

 

[Floandgary]

Stir it up right after you take your SG reading..... Just enough to release some of the CO2 and get the must in suspension. Does a batch GOOD!!!

 

[Julie]

Definitely stir, I normally do it twice a day until sg is down aroun 1.010 and then I snap the lid down and add an airlock until it is below 1.000 normally around .994 and then rack to a carboy.

 

[pete1325]

Sounds like a plan.............thanks.

 

[dcbrown73]

Everyday during primary. The fermentation process requires oxygen.

 

[Stressbaby]

@pete1325,

For whites from grapes I no longer stir. I ferment cool (using ice packs and water bath), removing the lid only to add bentonite and nutrient and to check the SG. My whites are better since I adopted this regimen.

 

[dcbrown73]

@pete1325,

For whites from grapes I no longer stir. I ferment cool (using ice packs and water bath), removing the lid only to add bentonite and nutrient and to check the SG. My whites are better since I adopted this regimen.

This is due to the cooler slower fermentation correct? I read that in one of my winemaking books. Reds can benefit from warmer shorter fermentation and whites to longer cooler fermentation.

That said, I heard that fermenting whites in this fashion can provoke stalled fermentation in some cases, but I suppose you can take precautions to prevent that.

 

[Stressbaby]

This is due to the cooler slower fermentation correct? I read that in one of my winemaking books. Reds can benefit from warmer shorter fermentation and whites to longer cooler fermentation.

That said, I heard that fermenting whites in this fashion can provoke stalled fermentation in some cases, but I suppose you can take precautions to prevent that.

Correct. I don't seriously cool it down until end of lag phase, and then when it gets down around 1.020 or so, by design (or perhaps because I'm tired of changing ice packs every 4-6 hours) I let it drift up to be sure it finishes. Usually it goes into the carboy around 1.010 anyway.

I have bought all the components for an Arduino controlled peltier cooler to make this more precise, but I'm going to have to wait until bear cub #1, the engineer, comes home at Christmas to help me build and program it.

 

[dcbrown73]

Correct. I don't seriously cool it down until end of lag phase, and then when it gets down around 1.020 or so, by design (or perhaps because I'm tired of changing ice packs every 4-6 hours) I let it drift up to be sure it finishes. Usually it goes into the carboy around 1.010 anyway.

I have bought all the components for an Arduino controlled peltier cooler to make this more precise, but I'm going to have to wait until bear cub #1, the engineer, comes home at Christmas to help me build and program it.

Nice! I toy with electronics also. Both Audruio / RPi based and straight analog electronics. Currently working on more ham radio stuff though.

If you get it working, I would love to hear about it.

 

[bkisel]

Once or twice daily during primary (down to 1.020-1.000) just to stay involved with the process. It is however, in my experience, not necessary unless you've got grape skins, fruit bag or the like.

 

[LoveTheWine]

Correct. I don't seriously cool it down until end of lag phase, and then when it gets down around 1.020 or so, by design (or perhaps because I'm tired of changing ice packs every 4-6 hours) I let it drift up to be sure it finishes. Usually it goes into the carboy around 1.010 anyway.

I have bought all the components for an Arduino controlled peltier cooler to make this more precise, but I'm going to have to wait until bear cub #1, the engineer, comes home at Christmas to help me build and program it.

Being an amateur Brewer (as well as winemaker) I have a dedicated temperature controlled fridge. When I am brewing a lager or Belgian or making a white wine, just set the temp and walk away. Cost nothing for the fridge and 30$ for the temp controller.

 

[Stressbaby]

Being an amateur Brewer (as well as winemaker) I have a dedicated temperature controlled fridge. When I am brewing a lager or Belgian or making a white wine, just set the temp and walk away. Cost nothing for the fridge and 30$ for the temp controller.

Yep I could do that but this method 1) doesn't require a fridge; 2) supports any container size; 3) is a lot more interesting to build.

 

[Redbird1]

Correct. I don't seriously cool it down until end of lag phase, and then when it gets down around 1.020 or so, by design (or perhaps because I'm tired of changing ice packs every 4-6 hours) I let it drift up to be sure it finishes. Usually it goes into the carboy around 1.010 anyway.

I have bought all the components for an Arduino controlled peltier cooler to make this more precise, but I'm going to have to wait until bear cub #1, the engineer, comes home at Christmas to help me build and program it.

I just read up on Peltier coolers. How do you plan on applying it to your wine? Some sort of insulated enclosure? What materials are you planning on using? I'm very intrigued and would like something a little more controlled than the frozen water bottle dance.

 

[balatonwine]

The fermentation process requires oxygen.

FWIIW, from "The Biochemistry of Yeast":

It is true that aerating or oxygenating wort is generally beneficial to fermentation, but it is untrue to say that yeast requires oxygen to reproduce or that yeast uses oxygen to respire during fermentation. The misunderstanding may be subtle, but it is a misunderstanding nonetheless. Gaining a clear understanding of the truth about how yeast works not only sets us on sound technical foundations, but has practical applications as well.

 

[Johnd]

FWIIW, from "The Biochemistry of Yeast":

I was going to chime in as well, there's plenty of conflicting info about the role of oxygen, I've seen articles written both pro and con, like the one you posted, and like the one below, where Piambianchi states:

"Oxygen availability: Oxygen negatively impacts the quality of wine during late fermentation and aging. During active fermentation, the wine is protected against oxidation by yeast that quickly scavenges oxygen. At the onset of active fermentation, the yeast will benefit from a small amount of oxygen for critical cell functions in carrying out fermentation. If yeast is deprived of air, it could be inhibited and not complete the fermentation."

https://winemakermag.com/1078-understanding-yeasts

Fermentation is typically defined as an "anaerobic" process. There seems to be general agreement that the benefits, if any, occur prior to the onset of fermentation, and that contact should be avoided at the latter stages. Never really worried much about making sure my wine is oxygenated prior to pitching, dumping a kit into a bucket, or crushing / destemming / stirring must, I've always thought, provides plenty to get the party started, if required.

As far as the need to stir a must with no skins once fermentation is started, it doesn't seem to me to be a necessity, nor will it hurt anything when CO2 is being generated. I like to play in the wine, so I stir sometimes.

 

[Stressbaby]

I just read up on Peltier coolers. How do you plan on applying it to your wine? Some sort of insulated enclosure? What materials are you planning on using? I'm very intrigued and would like something a little more controlled than the frozen water bottle dance.

I don't plan to run the wine itself through the cooler. Rather I intend to put the fermentation bucket inside a larger bucket with water in it. Then I have a submersible pump which will circulate the "water bath" through the cooling block. I have temp probes which will connect to the Arduino which acts as a thermostat and recorder. The other nice thing about this is you can reverse the current on the peltier device and use this system to warm the wine as well.

I will make a full post on the device with detailed materials list, plans, and pics once we get it built - assuming it works - which it will because engineer son #1 is uber-smart and doesn't fail when it comes to these types of projects.

 

[balatonwine]

As far as the need to stir a must with no skins once fermentation is started, it doesn't seem to me to be a necessity, nor will it hurt anything when CO2 is being generated. I like to play in the wine, so I stir sometimes.

IMHO, for white wine, I think stirring during the primary is just a wine making style. To get the accumulating lees into suspension and rotated. And because of CO2 out gassing, and SO2 from k-meta still in the must, I doubt it really contributes any significant amounts of O2 to make that O2 either much of a benefit or a risk.