How many ITB sterile filter stable red wines?

If you were in a situation where sterile filtering is not any more work or money for you, if you have a stable red wine ( less than 1 g/L sugar and less than 0.05 g/L malate) would you go ahead and sterile filter it or not?

I am talking wine that is going to be distributed and be out on the shelves in wine shops etc.

Just curious what people out there are doing.

“Stable” is an interesting concept and may be a bit more all encompassing than just sugar/malic numbers.
For example, a scorpion test may reveal bacterial infection or their may be some Brett lingering at less than organoleptic sensitivity levels. Sulphur levels (and it’s regimen over elevage) are also important vis a vis pH.
Perhaps, others can add on here.
Every case is different, IMO; hence, no blue line rules.
Best, Jim


no. two winters and the wine is stable? no filtration.

I’ve never stable-filtered red wines. Either at the wineries where I’ve worked (mainly Pinot noir) or my own (Syrah, Grenache, Mourvedre, Carignan)

I think the problem is that the fine filter strips colour and possibly tannin from the wine. The problem with stripping tannin is that you won’t have the molecules there that permit ageing and sedimentation.

However, if you are making a simple, commercial red to be drunk within 24 months, I’m sure the big wineries sterile filter.

I love crossflow filtration. I know it’s nominal filtration, but we always get clean scorpions. We’ve been very pleased with the technology.

for the non cellar rats can you explain what a scorpion test is ?

Scorpions is just PCR amplification of a wine sample. It amplifies yeast/bacterial DNA if present in the wine, so it can detect very low levels of these things.

Jon, you say you’ve never done this, then you talk about what it does. Have you tasted samples of the same wine where one has been sterile filtered and one has not? Have you done that blind, with multiple different wines? If so, were you able to eliminate visual clues at to which was which?

Linda, have you done that kind of thing? Even if you haven’t done it blind, I’d still be interested. I think the blind setting is more important where there is some kind of negative preconception. What micron size would you be talking about?

I know there are wineries that are not big and make really good (not simple at all), ageworthy reds that do sterile filter.

Bigger reds seem to recover faster and handle the additional processing better than Pinot Noir. I have found that with lower alcohol wines that are sterile filtered it removes much of the mouthfeel . I have done lots and lots of blind tastings of filtered and unfiltered wines over the years and I always prefer the unfiltered from beginning to 5+ years down the road.

Most wines I’ve made over the years were unfiltered, even many whites. Our current production does not see any finning or filtration for PN, SaviB or Semillion.

If your going to filter get a scorpion to see what present. Not every spillage organism needs a .45 filtration to be removed.

Thanks, Joe, that’s exactly the type of thing I was looking for. I suspect Linda will have a different set of experiences, but this seems to be one of those areas of very little agreement in the wine world. I have read that SB tends to have high levels of colloids. Do you ever have a problem with that where you don’t even fine it? Is settling and racking enough for you, or is there something else you do?

1-2 rack and backs and single level storage (no stacking or moving of the barrels) in the cellar seem to work just fine for us. I don’t add anything but so2 post wild yeast and malo ferments. We press it with our wooden slatted hydraulic basket press and only get about 135 gallons per ton. I only make 75-125 cases (one press load) right now. The press juice is quite clean and I have not had any problems other than to communicate to our customers to chill before drinking as to not throw tartrates.

I’ve done sterile filtration at university and on test wines and I felt, backed up by pretty much all research, that it strips character. To be honest, with modern winemaking and the understanding that we have of wine science, the only reason to sterile filter a red if if there is residual or added sugar. Ann even then, I bet those wineries that add sugar pasteurise rather than filter.

Pasteurize? Maybe the largest of the large guys, but not anyone I am aware of.

While I used to believe that, I have had very good luck with cross-flow filtering. I have had wines go into cross-flow that came out smelling and tasting better than prior. And I have yet to have one come out with less character or what I considered to be worse.
Big fan here.
Best, Jim

Nothing like personal experience to solidify the answer.

Having used up my sarcasm, I’m with Jim.

Really is an interesting thing having worked on both sides of the coin. For my personal project, and at my previous employer, I’ve never filtered a Pinot, though certainly have done it for Zin and Chardonnay (when not stable). I have felt that immediately post filtration, there is not necessarily a huge difference in the wines, but having tasted trials after 4, 5 and 7 years (same wine), tasted blind, there was a noticeable difference.

The wines followed a standard protocol right up until bottling and were ML and RS complete. Plating for brett and with a 4EP/4EG run showed nothing. No pump was used to move the wine at any point, wines were racked once and were put to the same tank for bottling. Filtration occurred on a small portion (pad filtration) with a desired NTU of less than 1. The wine that was unfiltered was bottled with an NTU around 35.

The results were simple, yet conclusive. They were different. Whether one was “better” than the other is a matter of debate. The filtered wine was noticeably brighter in color throughout the trials, but had a more “fruit” nose. The unfiltered wine was younger looking, with a decidedly more “pinot” noise- more forest floor and mushroomy notes.

Better or worse? I liked the unfiltered. The room though was split, 4-2 unfiltered.

Better or worse–always the problem in a world of subjectivity, but your description of the results for the unfiltered is exactly why people filter. Those forest floors and mushrooms are a potential short step away from disaster–or maybe not.

I have only herd of pasteurization on Koser wines made in non Koser facilities.

For those of you sterile filtering are you doing it twice? As in the cellar and then again in line or on the bottling truck? Do you then also dose velcorin at the bottling line? Mobile bottlers I have spoke with mention double sterile filter plus velcorin as getting to be pretty standard for those going down that path these days. Some mobile lines won’t even allow a “straight pipe” wine thru for fear of skins or seeds getting stuck somewhere in the line.

How do you deal with losing so much dissolved co2 in all that processing? Just let it be or add it back? I have actually been racking the wines one more time in recent vintages from having to much dissolved co2 in the wines, 800+.

If i ever had to mobile crossflow would be the way I would go. The examples I have tasted thru that process seem to be less effected.

In the FWIW column Louis Latour flash pasteurizes their wines.