Residual sugar question

[Smok1]

Ive been researching definitions of dry, semi-dry, and sweet wines in correlations to the amounts of residual sugar left in the wine, so far ive found
Dry: less than 10grams per liter
Semi-dry 10-30grams per liter
Sweet: anything over 30 grams per liter
(These are average as ive found conflicting amounts depending on what website im on)
The one thing i noticed is i read commercial winemakers tend to stop fermentation before the yeast has a chance to eat all the sugar to make semi-dry wines. So i guess my question is why do we use the rule of thumb to ferment dry and then backsweeten after to get a semi-dry wine? How would one go about stopping an active fermentation to create a semi-dry wine using the fruits natural sugars? Big dose of kmeta and then sorbate? Or is this a no no in home wine making?

 

[Johnd]

The one thing i noticed is i read commercial winemakers tend to stop fermentation before the yeast has a chance to eat all the sugar to make semi-dry wines. So i guess my question is why do we use the rule of thumb to ferment dry and then backsweeten after to get a semi-dry wine? How would one go about stopping an active fermentation to create a semi-dry wine using the fruits natural sugars? Big dose of kmeta and then sorbate? Or is this a no no in home wine making?

For me, it's much more of a matter of predictability. I know I can ferment to dry and, with a large degree of certainty, hit a specific ABV. From there, sweeten with control to exactly what tastes right, even over a period of time as the taste evolves, as long as you don't overshoot the sweetening in the beginning.

Trying to stop and active fermentation is not nearly so precise for me, and other than fortifying a wine to take the ABV above the toxicity limit by adding alcohol, don't know that I could do it effectively. Even cold crashing to stop the yeast, adding sulfite and sorbate, may not arrest the fermentation at exactly the point you want. It'd take a while to cool the must, which would still be fermenting to a degree the whole time the temps drop.

Sulfite certainly stuns yeast, but we use yeasts that are sulfite tolerant by design, to allow them to take over fermentations where other yeasts may already exist, and sorbate doesn't kill yeast, it only keeps if from multiplying. If you have an actively fermenting yeast colony, it will continue to ferment in the presence of sorbate until the sugars are gone or until they all die off of old age and can't reproduce.

So that's my answer: Predictability and control, FWIW..........

 

[Smok1]

Makes sense. Thank you.

 

[jburtner]

If this is true re; commercial winemakers "not fermenting dry" then there must be something to do with working with much larger volumes of fermenting wines that plays into back sweetening and mixing or some other situation where stopping an active fermentation is more productive >??

I am interested. Do you have references to this activity?

Thanks!
-johann

 

[Smok1]

If this is true re; commercial winemakers "not fermenting dry" then there must be something to do with working with much larger volumes of fermenting wines that plays into back sweetening and mixing or some other situation where stopping an active fermentation is more productive >??

I am interested. Do you have references to this activity?

Thanks!
-johann

Yes, heres a snapshot from a website showing they stop fermentation before all the sugars are eaten. You can search this on many websites. Plus the reason i was researching it is because my company has air conditioning contracts at many of the local vineyards/wineries in the area and while i was working at Monte Creek winery i was talking to there winemakers about residual sugar in there blueberry wine and he told me that they stop the fermentation at 1.008 sg to maintain some of the blueberries natural flavors. He wouldnt say much more about it probly because those guys like to have there secrets but i do know that some (at least) commercial winemakers use this method.

 

[drainsurgeon]

Its a no-no, and this is why; http://www.eckraus.com/wine-making-stop-fermentation

 

[stickman]

There are several ways to stop a fermentation commercially, but the equipment involved with yeast removal, such as a centrifuge, is expensive and not practical for the typical volumes fermented by home winemakers. That's the main reason for the standard home wine-making practice of fermenting dry followed by back sweetening.

 

[Scooter68]

There is the option of filtration with a sterile filter of .45 micron - Unfortunately most 'sterile' filters sold are .5 microns and while very close, that .05 difference is apparently enough to allow bacteria through, * which can still consume the sugar in your wine. Not to mention the cost of filters and equipment. And the fact that ANY leakage or wayward yeast cell that finds itself in you wine can still restart the process.

Comes back to the time, effort and risk involved

*https://winemakermag.com/365-how-do-you-sterile-filter-your-wine