I’m writing about Polyvinyl polypyrrolidone for a school project and am curious about peoples impressions of it. In Germany we don’t really use it for tannin reduction, but it is sometimes used to remove pigment from Blanc de Noir. Any negative effects (especially after filtration)?
Thanks,
Bill
no negative effects that I can sense - it’s great for pigment / browning removal. The one thing you can’t do with PVPP added wine is run it through a crossflow (will ruin your filters).
Props for the spelling! I usually give up after “poly vinyl”. 
I sometimes use it.
It can strip flavours if overused (as with many fining agents).
I tend to use it to reduce the phenolic pick-up from machine harvested fruit; and it’s also handy to prevent “pinking” in Sauvignon Blanc.
Only used in once on a Rhone blend that had some bitter tannins. It worked great, and the wine was much better afterwards.
That squares with what I’ve read abouts its use in red wine – that it has particular affinity for monomeric tannins and will leave your better polymerized tannins in place.
I’ve tried to do a few bench trials with it, but I’ve found it next to impossible to pipette and have ended up abandoning the effort.
I have not used PVPP for grape juice or wine but I have used it >10K times on plant extracts to eliminate tannins from the extracts for further separation of secondary metabolite components. The primary property of PVPP, a form of nylon, is that it is supposed to mimic protein structure. It was used for the first isolation of plant proteins by binding polyphenolic structures like tannins from plant extracts. You can dial in some selectivity but it is likely to be around the smaller phenolic molecules. In general the larger the molecule with phenolic groups the tighter it binds…energy binding characteristics at work over multiple points, alignment, and distance. You can take away that energy by oxidizing/reacting/capping phenols to quinones and quinone like structures, which some of the “aged” polymeric tannins do have. You should be able to bench trial with food safe pellicular PVPP where you can either gravity feed or use slight N2 pressure to pass juice/wine. …Gary
Thanks for the responses. The general consensus with the winemakers that I’ve talked to here is that it is often too aggressive and so isn’t very widely used. As for pigment removal, we had some very good success this year removing pigment from a Pinot Gris with far too much rose-color (from about 30 hours maceration time) by racking it off the lees and then reincorporating lees from another PG that we did whole cluster. I like the idea of using that technique with Gewürztraminer too.
Cheers,
Bill