Sugar question with malo

[havlikn]

I have a white wine that is at .994 sg. The wine went through malo. I want to add a touch of sugar to sweeten. I know I can’t add sorbate since I did malo.

Is there any way to calculate how much sugar I can add to prevent yeast from refermenting in the bottle?

 

[Ajmassa]

I believe running the wine through a .5 micron sterile filter is an accepted method to remove any active yeast cells remaining without using sorbate.
But a filter that is fine enough to remove a single yeast cell could also remove other desirable aspects too- but probably not as big of a deal on white wines.

 

[GreginND]

No, filtration does not remove color or flavors. That is a myth. It is hard to do a proper sterile filtration at home. You need to have a cartridge membrane filter with an absolute 0.45 micron filter at least. And you need to have impeccably sterilized hoses, bottling lines and bottles. Not easy to attain without commercial steam or ozone equipment. So, it is a risk. At home I would suggest you sweeten with a non-fermentable sweetener such as stevia, monk fruit or something like that.

 

[user 36973]

The wine went through malo. I want to add a touch of sugar to sweeten. I know I can’t add sorbate since I did malo.

Malolactic bacteria is easily controlled with sulfites. Dose your wine with proper (or even up to say 50% higher) sulfites along with the sorbate, as you would for any other wine, and you will be fine. I might stagger the dosing and allow the sulfites a week to sanitize the wine before adding the sorbate if the ML were recently working.

The problem with sorbate and ML (or any other bacteria) is when the sulfite level is too low.

Is there any way to calculate how much sugar I can add to prevent yeast from refermenting in the bottle?

Very difficult to remove all the yeast. Even with sterile filtration of the wine, any contamination of the hosing, fittings, gaskets, bottles, etc... can supply yeast that will hungrily work on the sugar.

 

[Ajmassa]

No, filtration does not remove color or flavors. That is a myth..

Good call on the sugar substitute to sweeten Greg. I had “duh” moment reading your reply.
What makes you say filtration stripping color is a myth tho? I have had this happen to me actually. Tho it might have been an isolated incident given the type of wine. It was a blend of 66% white and 33% red— yet still looked like a medium bodied red wine. After filtering with 1-2 micron pads it lost a lot of color now looking like a darker blush. No flavor lost.

 

[havlikn]

So what I’m reading is if I have a high enough so2 I can get away with sorbate and sugar even after doing malo?

I have always read if ever did malo, no option for sorbate

 

[Johnd]

So what I’m reading is if I have a high enough so2 I can get away with sorbate and sugar even after doing malo?

I have always read if ever did malo, no option for sorbate

That is not a risk I’d ever take, glycerin would be my first choice were i ever in a position to be forced to sweeten a wine that had undergone MLF. Not only will glycerin sweeten, it may also improve the mouthfeel and body of your wine, and I don’t recall any conflicts with MLF.

 

[user 36973]

I have always read if ever did malo, no option for sorbate

The key is to finish MLF, sulfite and then add the sorbate. Here is a short primer on MLF from Presqu'Isle which both makes/sells its wine and also sells supplies:
http://www.piwine.com/introduction-malo-lactic-cultures.html

Quoting their article "If a malolactic fermentation is encouraged, do not add potassium sorbate or potassium metabisulfite until the malolactic fermentation is complete."

 

[ceeaton]

This is what I've read before in Daniel Pambianchi's book Techniques In Home Winemaking:

http://www.techniquesinhomewinemaking.com/home winemaking geranium.html

 

[Stressbaby]

What makes you say filtration stripping color is a myth tho? I have had this happen to me actually. Tho it might have been an isolated incident given the type of wine. It was a blend of 66% white and 33% red— yet still looked like a medium bodied red wine. After filtering with 1-2 micron pads it lost a lot of color now looking like a darker blush. No flavor lost.

It is possible that some aspect of filtering, like oxidation, caused loss of color in the wine.

It is not possible that a 0.5 micron filter trapped color molecules in the wine.

A carbon ring is on the order of 1.5 Angstroms. Anthrocyanins, to use that example, are roughly the size of 4 carbon rings. So the molecule counting side chains, is on the order of 10 Angstroms or less in size. That is 0.001 microns, or 50 orders of magnitude smaller than the size of a 0.5 micron filter.

 

[user 36973]

It is possible that some aspect of filtering, like oxidation, caused loss of color in the wine.

I routinely filter my sweet wines down to 0.45um membrane and do not notice a substantial loss in color. I only do the dry red wines to 1um. What I do notice though is that suspended yeast in the wine gives the perception of addition color since it tends to scatter light, so when these particles are removed the wine is clearer and may be perceived as having less color.

A carbon ring is on the order of 1.5 Angstroms. Anthrocyanins, to use that example, are roughly the size of 4 carbon rings. So the molecule counting side chains, is on the order of 10 Angstroms or less in size. That is 0.001 microns, or 50 orders of magnitude smaller than the size of a 0.5 micron filter.

You probably mean 1.5nm rather than Angstroms for the carbon ring (each C-C bond is about 1.5A). Regardless, I agree that the physical filtering is unlikely to impede even the large tannin-anthocyanin complexes. Any loss in pigments may rather be due to absorption in the filter pad material rather than blockage.

 

[sour_grapes]

Here was my take on this issue (and yes, I ran the numbers for this analogy):

I know there are a few that will disagree with me, but I filter all my wines down to 1 micron, whites and reds. Most commercial vineyards go down to almost .5 to achieve a sterile filter... I remember hearing once that flavour molecules compared to sterile filter is like throwing a ping pong ball through soccer netting. In other words flavour molecules much too small to get caught in any filter we could do at home.

Not bad, but not dramatic enough. If the "flavor molecules" are the size of a ping pong ball, the gaps in the filter would be more like the distance BETWEEN THE SOCCER GOALS (on opposite ends of the soccer pitch).

In the current thread, @jgmillr1 hits on an issue I have long wondered about, but have no way to assess:

Any loss in pigments may rather be due to absorption in the filter pad material rather than blockage.

What do filter pads look like after filtering a red wine? I have never filtered, so have not idea what to expect.

 

[Ajmassa]

Doubt this is typical though. This was a problem batch and the first time I filtered. A plate filter but gravity fed. Obviously you can see where I started before I got the hang of it. I did rough 2-7 microns and medium 1-2 micron I think. 1.5 yrs old at the time and had oxidized and browned some before filtering. But looked like a rosè afterwards. I attributed it to the perfect storm being 66%white blend and having bacteria via o2 before filtering.
“Color loss through pad material absorption rather than blockage” —- what do you mean by blockage?

 

[user 36973]

What do filter pads look like after filtering a red wine?

The filter pads in the picture above look typical. You get a film a yeast sludge on the surface of the initial rough filtration and subsequent fine filtering looks more like just stained pads.

“Color loss through pad material absorption rather than blockage” —- what do you mean by blockage?

I mean that filter pads work by creating a convoluted pathway for particles to have to get through in order to make it to the other side. The tighter the pathway, the smaller the particles must be to get through. Likewise for membrane filters where the holes in the membrane are precisely sized to prevent passage of anything larger. So, by "blockage" I'm referring to the physical separation from the liquid stream.

Whereas "absorption" I'm envisioning more of a chemical bonding process that binds the anthocyanin molecules out of solution. The extreme example of that the use of a carbon filter pad or some fining agents. I have not noticed any significant color reduction though in either filter pad use down to a 0.5um rating or 0.45um membrane filtering.