POLL: Diamonds of Wine?

How does everyone feel about the "diamonds of wine" or those potassium tartrate (cream of tartar) crystals you sometimes get in the bottom of your glass from a wine that hasn't been fully cold-stabilized? Personally I don't mind them and sometimes even chew on them a bit, but I've seen people who don't know what they are recoil in horror thinking that there is glass in the wine. Some claim that they're a sign of quality, but I'm not sure that supersaturation with KHTa correlates with quality nor does cold stabilization (which precipitates the KHta prior to bottling) decrease quality.

What's your take?

I've never seen them, noticed them or knowingly felt them before to be honest! Does this mean I'm not drinking or paying attention to enough wines perhaps? Or perhaps just the wrong ones?

Jeff

I get tartaric crystals in my homemade wine quite often. To eliminate, you can decant or just be careful pouring that last glass. Even though I know what they are and know they are harmless, I try to avoid getting them in my glass-- mainly because I don't want to be startled by a c-r-u-n-c-h after taking that last sip in the last glass. I have eaten tartaric crystals on purpose, just to see what they are like.

I wouldn't say that tartaric crystals were a sign of higher quality, though they are not a flaw, either. It is merely tartaric acid crystallizing and falling out of solution. It is an indication the wine was not cold stabilized. Cold stabilization will force the issue so to speak. Tartaric crystals will form and fall out, enabling the wine maker to rack-off the crystals. Some might see cold stabilizing a wine as a flaw, while others might see not cold stabilizing as a flaw.

OK, I'llput my head above the parapet.

I'll say they are an indicator of quality. You don't find them in mass market over manipulated wines.

Having them doesn't make it a quality wine but you sure don't find them in mass wines.

[David M. Bueker]

Peter - the only action that has to be taken to avoid them is chilling the wine below a certain temperature (don't recall the exact temp) & then letting them settle before bottling. That's not exactly a mass market manipulation.

edited to add: I don't care about them one way or the other.

Peter - the only action that has to be taken to avoid them is chilling the wine below a certain temperature (don't recall the exact temp) & then letting them settle before bottling...

Usually around 23 degF (-5 degC) for about two weeks. The wine is then separated from the crystals while the win is still cold, either by racking or by coarse filtration. It should be pointed out that tartrates are not only less soluble in cold wine, but also less soluble as the alcohol content rises. Lots of tartrates fall out of solution during fermentation. Sometimes the tartrates are refined and sold as cream of tartar. I will add that the tartrates are formed because grapes contain tartaric acid and grapes are one of the few fruits that contain tartaric acid (I think a few types of berries also contain it).

I find all manner of precipitates and sediment fascinating.

When I get them in sweet wines my brain always seems to suggest they'll be sweet like sugar - but they never are

Overall, I'd say they were a moderate annoyance, but one I don't mind especially.

regards

Ian

Crystals are fascinating to look at and contemplate. I love looking at those KHT crystals to see if I can detect inclusions of the anthocyanin colorants from red wine. They often look dark, but I have yet to convince myself that the crystal itself has included the color within it.

Mark Lipton

Peter - the only action that has to be taken to avoid them is chilling the wine below a certain temperature (don't recall the exact temp) & then letting them settle before bottling. That's not exactly a mass market manipulation.

Yes I know; been there, seen it.

Big producers selling mass market do it. It is manipulation for the mass market.

I've never seen them, noticed them or knowingly felt them before to be honest! Does this mean I'm not drinking or paying attention to enough wines perhaps? Or perhaps just the wrong ones?

Jeff

Hard to say. If you like red wines it's possible that you saw them and just lumped them in under "sediment". In whites they're often confused with sand or glass by people who haven't come across them before. The crystals are really sand-size, not 1ct diamond size. Many white producers do cold stabilize to eliminate the possibility of crystals forming, but many don't. So if you haven't come across them yet, keep drinking!

Peter - the only action that has to be taken to avoid them is chilling the wine below a certain temperature (don't recall the exact temp) & then letting them settle before bottling. That's not exactly a mass market manipulation.

Yes I know; been there, seen it.

Big producers selling mass market do it. It is manipulation for the mass market.

Definitely, they don't want to confuse the general buying public who don't understand what it is.

However, some smaller good producers cold-stabilize as well, so it's not exclusively a mass-market thing. I haven't seen any data suggesting that it has any impact on the quality of the wine, so I think it's a relatively benign manipulation.

John

I've never seen them, noticed them or knowingly felt them before to be honest! Does this mean I'm not drinking or paying attention to enough wines perhaps? Or perhaps just the wrong ones?

Jeff

Hard to say. If you like red wines it's possible that you saw them and just lumped them in under "sediment". In whites they're often confused with sand or glass by people who haven't come across them before. The crystals are really sand-size, not 1ct diamond size. Many white producers do cold stabilize to eliminate the possibility of crystals forming, but many don't. So if you haven't come across them yet, keep drinking!

Thanks for the explanation. I may have unknowingly noticed them in reds once in a great while but as you mentioned I probably just assumed it was "sediment". Although this may make me very odd and unusal, I've never decanted a wine before either. Whether it "needs" it or not, I just pop the cork, pour and enjoy. I do often let the glass of wine itself sit for a few minutes (I typically linger over a glass or two unless its SO delicious that I cant help myself take quick sips) but I never decant the bottle as a whole. I suspect if I did I might notice bottom of the bottle sediment/crystals more easily.

Jeff

Back in the day we had a great discussion on the old WLDG about acidity and pH. (Thanks to Alan, Howie, Paul, and others). Cold stabilization could be looked as a great tool for a winemaker. Depending upon the starting pH, if it is less than 3.6, prior to cold stabilization one can experience a decrease in TA (total acidity) and only a subtle or slight decrease in pH. On the other hand if the starting pH, is greater than 3.6, prior to cold stabilization one may experience not only a decrease in TA but also an increase in pH.
Not really manipulation but trying to keep or maintain balance, if you will.

Salute

I'm ambivalent towards them at the bottom of my glass but I love it when the crystals grow off the bottom of the cork.

The crystals are really sand-size, not 1ct diamond size.

While I agree I have never seen one as large as a 1 ct diamond, I have seen them as large as roughly a 1/3 ct diamond in a muscat that carried about 2%RS. Not sure if the sugar content made them larger or not but they were impressive and often confused for glass shards in the bottle.

Peter - the only action that has to be taken to avoid them is chilling the wine below a certain temperature (don't recall the exact temp) & then letting them settle before bottling. That's not exactly a mass market manipulation.

Yes I know; been there, seen it.

Big producers selling mass market do it. It is manipulation for the mass market.

Definitely, they don't want to confuse the general buying public who don't understand what it is.

However, some smaller good producers cold-stabilize as well, so it's not exclusively a mass-market thing. I haven't seen any data suggesting that it has any impact on the quality of the wine, so I think it's a relatively benign manipulation.

John

I have heard winemakers say that the wine is diminished, at least to some extent, by cold stabilisation, and many avoid it for that reason. I tell my producers that my customers are sophisticated enough to know that tartrates aren't a problem, and in most cases they settle to the bottom so easily that they are easy to avoid, at least at home. If a wine is being poured by the glass in a restaurant you end up with a sort of snow globe effect...

I have heard winemakers say that the wine is diminished, at least to some extent, by cold stabilisation, and many avoid it for that reason...

I don't know how much it is diminished, but cold stabilization reduces the acidity. If the tartrates settle out over time, you can get the snow globe effect. However, especially in whites, at room temperature, a wine will be perfectly clear, but when it is put in the fridge before serving, the tartrates will fall out of solution as extremely fine particles that don't settle and the wine will become cloudy.

The crystals are really sand-size, not 1ct diamond size.

While I agree I have never seen one as large as a 1 ct diamond, I have seen them as large as roughly a 1/3 ct diamond in a muscat that carried about 2%RS. Not sure if the sugar content made them larger or not but they were impressive and often confused for glass shards in the bottle.

I have a collection of corks with tartrate crystals on them, both red and white. Definitely bigger than sand sized. One of these days I will find out how to photograph them with the digital camera. Or maybe I should dredge out the old Olympus OM2 and some film.

I have heard winemakers say that the wine is diminished, at least to some extent, by cold stabilisation, and many avoid it for that reason...

I don't know how much it is diminished, but cold stabilization reduces the acidity. If the tartrates settle out over time, you can get the snow globe effect. However, especially in whites, at room temperature, a wine will be perfectly clear, but when it is put in the fridge before serving, the tartrates will fall out of solution as extremely fine particles that don't settle and the wine will become cloudy.

I thought that the cloudiness in the wine was generally a protein haze. When tartrates fall out of solution, they should do it as crystals, though perhaps ones small in size.

Mark Lipton

I have heard winemakers say that the wine is diminished, at least to some extent, by cold stabilisation, and many avoid it for that reason...

I don't know how much it is diminished, but cold stabilization reduces the acidity. If the tartrates settle out over time, you can get the snow globe effect. However, especially in whites, at room temperature, a wine will be perfectly clear, but when it is put in the fridge before serving, the tartrates will fall out of solution as extremely fine particles that don't settle and the wine will become cloudy.

Good points- I'm sure in some cases cold-stabilization could diminish a wine, though in the case of under-ripe grapes and whopping TA a little seeding with cream of tarter followed by cold-stabilization could certainly improve the wine as well. The winemaker has to decide based on best judgement, just like any of the other decisions a winemaker makes at each step of the process.

I think Howie is right that you could get some cloudiness under the right conditions due to tartrates, but it's also a classic sign of protein haze. Many whites are fined with bentonite to prevent that, but over-fining can strip character as well.

John

John wrote;
Many whites are fined with bentonite to prevent that, but over-fining can strip character as well.

Definitely agree with you and Oliver that over-fining and over-handling a wine can be detrimental. This is why most winemakers will “combine” or “time” certain winemaking techniques. As for bentonite fining (if done properly and in a timely manner) to prevent protein instability IMHO is a lot less harmful (to the wine, and in my case being an amateur winemaker easier to perform and safer) than say heat stabilization (exposing the wine to high temperatures for a given duration of time). Cold stabilization (to remove excess acid), if done in a timely manner (timing it to a scheduled racking for instance) IMHO is one of the gentlest winemaking techniques one can perform on the wine. The only danger is that at low temperatures the wine can easily oxidize.
As far as if one is to perform a cold, heat stabilization, micro-filter the wine, one most consider- how is the wine sold? Is it distributed nationally and internationally or is just sold locally from the winery itself. If you’re a large producer of wine and your wine is shipped all around the world and there is a possibility it could be stored in not so ideal conditions you might want to consider stabilizing the wine. Its just everyday QC-Quality Control.

Salute

Finings are used to speed the clearing of wine. Many will argue that excessive finings will harm the quality. Many will also argue that filtering or at least using a fine filter will also affect the quality. The trade-off for a producer is getting the wine in the bottle quicker. Many home winemakers will use few if any finings and don't filter. If you leave wine in a container long enough, degass it, and rack periodically, it will typically clear given enough time.

If one were worried about quality, one would only perform cold stabilization as a means to reduce acidity (tartaric acid to be specific). That might definitely enhance a wine that was otherwise too acidic. However, if one only cold stabilizes to remove tartaric crystals so they don't form later, one might be lowering the acidity of a wine that was already pretty well balanced.

Finings are used to speed the clearing of wine. Many will argue that excessive finings will harm the quality. Many will also argue that filtering or at least using a fine filter will also affect the quality. The trade-off for a producer is getting the wine in the bottle quicker. Many home winemakers will use few if any finings and don't filter. If you leave wine in a container long enough, degass it, and rack periodically, it will typically clear given enough time.

If one were worried about quality, one would only perform cold stabilization as a means to reduce acidity (tartaric acid to be specific). That might definitely enhance a wine that was otherwise too acidic. However, if one only cold stabilizes to remove tartaric crystals so they don't form later, one might be lowering the acidity of a wine that was already pretty well balanced.

IME cold stabilisation is used to prevent the formation of tartrate chrystals in the bottle, because the winery is worried that their consumer won't understand the deposit, rather than to fine-tune the flavor.

My worst example of a deposit was a Barbera d'Asti that seemed to have been left too long in the truck in Piedmont in February, a sort of accidental cold stabilisation.