# Importance For Stirring Your Must



## djrockinsteve (Feb 6, 2011)

Importance For Stirring Your Must

Stirring your must several times per day (at least twice) helps your must in several ways.

First you are keeping your "cap", the fruit moist to help prevent oxidation by pushing the fruit back down. Fruit rises from The CO2 that is given off by the yeasts.

Second you are releasing CO2 (Carbon Dioxide, and other gasses) from your primary to make it easier on the yeast to do their job. If there is too much CO2 in your must the yeasts will become strained and you may stall a fermentation.

Third you are mixing in air which contains oxygen into your must. Yeast need to breath. By stirring not only are you adding much needed oxygen to your must you are releasing CO2 at the same time.

Forth by stirring and releasing CO2 this is that much less degassing you will have to do when your must turns into wine.

Fifth by stirring you are mixing the yeasts and the nutrients around making it easier for them to do their work. Even yeast that have fallen to the bottom of your primary will aid in the process of making wine.

Photo one shows a primary containing crab apples prior to stirring.







Photo two shows immediately after stirring. Crab apples have a natural tendancy to float. Many fruits will sink.






Even if you do not have fruit in your must it is still important to stir your must frequently.


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## terroirdejeroir (Oct 8, 2012)

I have always stirred the must in primary until the fruit is removed. Is there a benefit to stirring in secondary as well? I have a raspberry mead that is moving along rather slowly and I was just wondering if I should stir it up a bit.


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## Ricky (Oct 21, 2012)

Fellow Pa person....lol ... is this for kits as well as juice, and grapes.... stirring the must ...for the yeastie`s


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## Pumpkinman (Oct 22, 2012)

Ricky, I'm currently making several different batches of wine from Juice, as soon as I started to stirring the wine several times a day, the fermentation took off really well. 
I suggested stirring the wine to a friend that also is making wine from Juice, he had a batch that had a slight sulfur smell, after stirring several times a day for 4 days, the wine no longer smells of sulfur!
I highly recommend it!


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## Hooliorama (Apr 3, 2013)

djrockinsteve said:


> Importance For Stirring Your Must
> 
> Stirring your must several times per day (at least twice) helps your must in several ways.
> 
> ...



I read that stirring can help reduce sulphite (added previously of resultant from yeast fermentation) which can be good if you have too much.... But can also drop the sulphites below a minimum needed to protect against souring.


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## Julie (Apr 4, 2013)

this is during fermentation not after, you would not have any sulfites in your must at this point.


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## olusteebus (Apr 4, 2013)

I started two WE coastal whites Sunday. I put raisins and oak in the primary. The instructions called for no stirring. Should I or should I not stir them?


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## djrockinsteve (Apr 4, 2013)

Best would be to get an answer from someone who made this kit. With that being said I have seen on here many people who make kit wines encounter trouble. Usually from not following directions or perhaps making wine that contradicts the science. 

Kit manufacturers obviously want you to follow their directions but we do not know their exact reasons. 

As long as it has ample oxygen and its fermenting nicely let it be b


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## SPAF (Apr 5, 2013)

I don't really understand this: "Third you are mixing in air which contains oxygen into your must....By stirring not only are you adding much needed oxygen to your must..,."

If you introduce oxygen to yeast during anaerobic respiration, I.e. fermentation, then the process will shift over to aerobic respiration which has completely different by-products not including ethanol. Can you explain?


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## theTheme (Jan 17, 2014)

SPAF said:


> I don't really understand this: "Third you are mixing in air which contains oxygen into your must....By stirring not only are you adding much needed oxygen to your must..,."
> 
> If you introduce oxygen to yeast during anaerobic respiration, I.e. fermentation, then the process will shift over to aerobic respiration which has completely different by-products not including ethanol. Can you explain?



Can someone follow up on this? I am on my second batch and have been stirring twice a day. The SG fell and is falling nicely on both batches. But, I had a little freak out moment when I read this article that says not to stir and further to put an airlock on so that as SPAF mentions, the anaerobic process will convert sugars to alcohol.

Forum searches seem to show that most of you don't airlock your primary. Can someone explain the science behind why this works?


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## djrockinsteve (Jan 17, 2014)

Gently stirring your must a few times a day mixes in some oxygen, you're not whipping it. Any fruit needs to be kept wet, sugars need to be moved around as so do the yeast.

You are also slowly releasing CO2 creating a slightly better environment for the yeast in a world that is slowly becoming hostile to them aka high alcohol % and lack of food.

Primaries are left uncovered except for a cloth or towel to keep pets etc. out. As the gravity reaches 1.000 some people transfer ALL contents of primary and airlock leaving space for the must to expand with temp. increases. When fermentation is complete they transfer off of the sediment (gross lees), stabilize and clear under airlock.

Some of us ferment dry in primary. I add a teaspoon of super ferment (a yeast booster) to 5 gallons, stir well to release CO2 and mix all sediment throughout which is good at this time. Then I immediately snap on a lid with an airlock. The CO2 being released from the must will push out oxygen which will start to become harmful to your wine.

The CO2 being heavier will lay upon your must, soon to be wine protecting it from the oxygen.

The lid keeps the must from exposure to fresh oxygen and being still for 2-3 days will allow much sediment to drop to bottom of bucket.

After 3 days usually for me my gravity is below .990. YES your gravity can dip below that point as evident of a refractometer. I now carefully siphon out wine leaving sediment behind into a carboy adding sulfite and I use sparkolloid for clearing. I fill to an inch below bung.

Many people I have read transfer or ferment in a carboy and ultimately encounter problems. There are way too many threads on here of such problems. Yeast need to breath and excess gasses which are not limited to CO2 are harmful to musts and wine.

With an active fermentation your must is protected from unnecessary CO2 and can turn into something wonderful.

There are books available to explain the scientific process if you really like to delve into it.

I liked the free download Wine Making manual by Lum Eisemen
http://www.winebook.webs.com

Well worth printing it out and reading. Warning it is lengthy and the prices are old but info is right on.


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## SPAF (Jan 17, 2014)

So I'm seeing this question I wrote about oxygen. Since then I realize the importance of yeast oxygenation during fermentation, chiefly to ensure a healthy yeast cell membrane culture. The stronger the yeast membranes, the more stressors the cells can withstand. Also, the ability to de-carbonate the must is a must. I now stir my fermentations twice per day every day.


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## SBWs (Jan 18, 2014)

This link called yeast 101 is what I go by as far as when to stir and when not to stir in oxygen. 

The way I understand it is yeast use sugar for two things the first is to reproduce the second is to make alcohol. If you keep stirring oxygen into your must you will keep the yeast reproducing and eating up sugar that won't be available for the yeast to make alcohol. 

The thing to remember is oxygen good first 2 or 3 days then not so good.

After that punch down cap and a little stirring won't hurt as gas will be released keeping oxygen from getting to the must. Just don't stir so much as to degas completely allowing oxygen in.


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