Newbie question

[Ldcecil]

Do you guys stir your wines every day? I see some say do and some say don’t.

 

[Jovimaple]

Do you guys stir your wines every day? I see some say do and some say don’t.

For kit wines, I follow the instructions, which generally say to leave it alone (although I check the SG and rack when it's done even if it's less time than the instructions say).

For non-kit wines, I typically make a yeast starter the night before, then carefully pour it in the next morning; within 6 to 12 hours I generally can smell and see the yeast has kicked off. After that I usually stir at least once a day for the next 4 days or so.

For Danger Dave's Dragonblood, I follow the recipe which says to stir daily until the SG is down to a certain point and the fruit is removed (going by memory - it's been a while since I made that).

Stirring isn't a big deal, if you ferment in a bucket with a towel over it, which is what I do. Since the yeast need O2 at first, stirring seems to help get them going.

 

[Jim Welch]

I do mostly open primary fermentation like most here. During the initial vigorous fermentation I stir at least a couple times a day for all my wines, if the wine has grapes I stir daily until it is racked off the skins at about 1.010 SG. If no skins I stop stirring once the foaming diminishes and rack also at about 1.010 SG
I have done a couple closed fermentations on white wine with no stirring though.

 

[winemaker81]

My current process uses an overnight starter. I add that and do not stir for 24 hours. If fermentation is obvious (and so far it always is), I stir at least once per day. For grapes or skin packs, I punch down 2 to 3 times per day.

 

[BigDaveK]

I think the simple answer is that it should be stirred daily especially if there's a hard cap. A build-up of CO2 can lead to a stuck fermentation.

I stir multiple times a day because I enjoy it! (And I taste every time!) The amount of CO2 determines how often I stir....

...or pour! I currently have a banana in primary. Slow ferment because I'm under 60F and it gave me a chance to experiment. It's VERY thick. Stirring will produce a 1 inch cap in a couple hours. I also poured it between buckets, back and forth. Each time after pouring within a couple hours my cap is 5 inches thick! Take from that what you will.

More complex answer -
Oxygen is important during fermentation. It's especially important during the first 48 hours. Oxygen is needed for reporoduction and also the production of lipids, fatty acids, and ergosterol which strengthen the cell wall, thereby being more resistant to high ethanol later, and thus avoiding a stuck fermentation.
Oxygen also affects the creation of esters, fatty acids, branched acids, ketones, aldehydes, and higher alcohols. Yeast metabolism is incredibly complex and interesting. So, yes, we want oxygen - but not too much.

If you're interested in a deep dive this is a good paper on oxygen and fermentation -

https://downloads.hindawi.com/journals/ijfs/2020/7902974.pdf

 

[Ldcecil]

I think the simple answer is that it should be stirred daily especially if there's a hard cap. A build-up of CO2 can lead to a stuck fermentation.

I stir multiple times a day because I enjoy it! (And I taste every time!) The amount of CO2 determines how often I stir....

...or pour! I currently have a banana in primary. Slow ferment because I'm under 60F and it gave me a chance to experiment. It's VERY thick. Stirring will produce a 1 inch cap in a couple hours. I also poured it between buckets, back and forth. Each time after pouring within a couple hours my cap is 5 inches thick! Take from that what you will.

More complex answer -
Oxygen is important during fermentation. It's especially important during the first 48 hours. Oxygen is needed for reporoduction and also the production of lipids, fatty acids, and ergosterol which strengthen the cell wall, thereby being more resistant to high ethanol later, and thus avoiding a stuck fermentation.
Oxygen also affects the creation of esters, fatty acids, branched acids, ketones, aldehydes, and higher alcohols. Yeast metabolism is incredibly complex and interesting. So, yes, we want oxygen - but not too much.

If you're interested in a deep dive this is a good paper on oxygen and fermentation -

https://downloads.hindawi.com/journals/ijfs/2020/7902974.pdf

Thanks, I will take a look. I am a biology/chemistry person and like to understand what is going on in the jug!