Tartrate crystals in my muscadine wine aged with oak chips

[Shellintx]

This is our first batch of muscadine wine. We aged half of it with oak chips for about a week. The flavor is great, but I noticed in ONLY the bottles we added oak chips to, we have a sediment at the bottom that appears to be tartrate crystals. I shook this bottle, so what was formed across the bottom of the bottle broke apart so you can see it better. The other dozen bottles have a white layer only visible if you look at them from the bottom. I cannot tell any difference in taste. Would you uncork, filter and rebottle? Is there a way of avoiding these in the future?

 

[winemaker81]

How much wine do you have? If it's a lot, I'd simply decant wines before drinking, leaving sediment behind.

If your wine is from this fall, you're not bulk aging long enough. I was originally taught to never bottle before 4 months. I've tried various periods, and came to the conclusion that even with modern fining agents, 4 months is a minimum, and red wines will have 6 to 12 months before bottling. This provides sufficient time for sediment to drop.

A test for tartrate crystals -- eat a few -- they'll crunch like tasteless sand in your mouth. A 3 yo wine dropped a half a dozen crystals in the bottle and I got to experience this last week, so the experience is fresh in my mind. Alternately you can do a visual inspection, see white flakes, and simply trust that it's tartrate crystals. [Go with Plan B as you won't have to rinse your mouth out. ]

As to why the oaked wine dropped crystals and the unoaked didn't? Chemistry. Something in the oak produced a nucleation point, so the crystals formed. My guess is the unoaked wine will form crystals at some point, since it's the same wine, so the acid levels are the same.

NC Muscadine is high acid, and my guess is that TX Muscadine is as well. Cold stabilization is the easiest acid reduction method and has the fewest side effects -- chill the wine to to the 30's F for a week or two -- the drop in temperature will lower the acid saturation point and crystals will drop. Rack off the crystals.

When I lived in Upstate NY, I put carboys of whites on my porch for a week or two, as my porch was in the 30's during the winter. My guess is that TX doesn't get that cold, so you can put the wine in 1 US gallon / 4 liter jugs and refrigerate. That will do the same thing, although if you have 50 gallons of wine it may not be the ideal solution. Many moons ago an acquaintance purchased an extra refrigerator, took out the shelves, and it fit two 19 liter carboys.

Note -- although "full" cold stabilization works if the temperature is close to freezing, it's not essential. If you can get the temperature below 50 F for a couple of weeks, it's likely your wine will drop enough crystals that you won't have any form in the bottle.

My cellar is typically 58 F in the winter, and over years wines with relatively low amounts of acid may drop crystals.

 

[Rice_Guy]

Having bitartrate crystals simply means the juice was high in acid. Some organic wine I have seen puts on a disclaimer saying natural wine sheds tartrates. As a northern grape grower this is normal, and suggests to me that the wine could have been in the carboy for some cold weather then racked off the tartrates.

 

[cmason1957]

I'm going to second what @Rice_Guy said. I mostly used Norton and/or Chambourcin for red wines. Both always go into the spare refrigerator turned down as low as it will go for two to four weeks. Always get tart rates dropping out and it helps the taste. I can't tell you how the numbers change after cold stabilization of either of these, since it doesn't matter to me, it just makes a better wine.

 

[dodahman]

This is our first batch of muscadine wine. We aged half of it with oak chips for about a week. The flavor is great, but I noticed in ONLY the bottles we added oak chips to, we have a sediment at the bottom that appears to be tartrate crystals. I shook this bottle, so what was formed across the bottom of the bottle broke apart so you can see it better. The other dozen bottles have a white layer only visible if you look at them from the bottom. I cannot tell any difference in taste. Would you uncork, filter and rebottle? Is there a way of avoiding these in the future?

I bet its just tartrate crystals. Harmless. Actually makes the wine taste better IMHO, less acidic. What you can do if you have a surplus fridge or a freezer, put the entire carboy in there. If its a freezer, it would take a couple of days before it starts freezing but the cold crash will force out the tartrates and then when the wine gets back to room temperature, just rack off.