My new rosé has elevated residual sugar to the tune of 12.4 g/l. Should I be concerned about possible refermentation in the bottle? I’m thinking yes. As I understand, there are a couple of possible remedies:
Add Potassium Sorbate. I see this used in sweet wines to control refermentation. It doesn’t kill yeast but
can inhibit yeast multiplying.
Or sterile filter the wine?
Filtration would be preferable and I found a rental unit that should work: Buon Vino Superjet.
Or should I add Sorbistat K and filter?
Local wine shop says to do both.
Rosé has good pH 3.31 so a little sugar makes it not too tart. Did not do malolactic fermentation.
I’d filter, but it’s hard to have a great deal of confidence in the cleanliness of any rental equipment. Whatever your normal sanitation protocol, take it up several notches on any part of the filter and hose that touches the wine. I wouldn’t accept any assurances that the unit is already clean and ready to go.
Linda, this is home winemaking.
Todd, I hoped it would be dry but post fermentation it tasted sweet so I sent samples to the lab
And came back with the elevated RS numbers. Last year’s rosé had 3 g/l for comparison.
Stewart, I hear you on the sanitation. I plan to sanitize before use.
I guess my question is should I use both Sorbistat K and sterile filtration or should filtration
Be sufficient? If possible I would prefer not to make additions unless necessary.
Having filtered a few whites this year (first time for me), I can tell you one thing - sterile filtering strips the wines enormously of flavor. It’s a world of difference. Not only that, it screws up your chemistry as well as not just particles get filtered out, but everything incl. potassium etc. You’ll have a much higher pH after filtering, guaranteed. That means adding acid, which will then most likely precipitate out as tartrates (unless it has been cold stabilized if it’s a white) etc. Honestly, if it’s just for home wine, I wouldn’t.
Why don’t you just do a restart instead? It’s a little time-consuming, but it works. Order some Uvaferm yeast, get a starter biome going and it’ll go dry. How much wine are we talking about?
What type of filtration are you using? Plate and frame? Cross flow does not strip the wine at all. And note that nearly all ‘flavor molecules’ are much smaller than even a .45 micron filter so they are not being ‘stripped out’ - perhaps beaten up a bit, but they are still there. And your chemistries should not change much if filtration is done well.
Larry, it was crossflow filtering for both. One had a VA problem so that went through RO (which of course is very invasive), so don’t really count that one. But even the other one that was just lightly crossflow-filtered stripped a lot of flavor and acid out of it. I was surprised it was as noticeable, because I’d been told the same.
That is some strange behavior right there. I’ve sterile filtered a lot of wines at lab scale and never observed a change in pH/TA as a result. RO definitely, but losing acid from a wine being lightly cross flow filtered is super weird…anyone else ever heard of this?
What Larry said. But at 0.2 micron you’re still not pulling out acid. The organic acids in wine are really small molecules. In theory you could remove a small amount of acid from red wines because of interactions between tannin colloids and acids but we’re talking really small changes there and I’ve never actually observed it myself. I’ve observed some compounds in wine adsorb onto some unusual filter materials and so decrease as a result of filtration but I can’t think of any filter materials that I would expect to interact with major wine acids this way.
Well, all I can say is that lab results before crossflow went from around 3.4 to 3.77pH. No info on TA, as they just did partial panel after CF. But it was two different labs, so could be a measuring error, I suppose.