Bet you didn’t know: Wine has a fair amount of protein in it!
Unfortunately, this does not mean that your glass of Chardonnay is going to help you bulk up on your Paleo diet. We actively try to remove the proteins found in wine, in order to remove cloudiness, and to prevent the wine from becoming hazy the bottle.
This step is important for our bottled wines, because once we put our wine into bottle and into the hands of a customer or distributor—there’s no telling what the wine’s going to go through. Maybe the wine is left in a hot car, or on a sunny windowsill, or on a picnic blanket on warm summer day. Any of these warm conditions will cause the proteins in the wine to coagulate and precipitate out of solution, making the wine cloudy.
Don’t get me wrong—hazy wine is still just as delicious and won’t hurt you to drink! It’s just not as visually appealing. However, leaving a bottle of wine in warm conditions for a significant amount of time (more than a couple of hours) can affect the flavor of the wine.
Most of the proteins found in wine will have a positive charge. This positive charge causes the proteins to repel each other (like the positive ends of two magnets would.) Hence the reason why the wine appears to have a haze to it—all those protein particles are repelling each other, and suspending themselves in solution.
In order to prevent our wines from becoming hazing, we do a step called Protein Stability, which removes the proteins from the wine, so they won’t cause a hazy reaction. We do this by adding a slurry of Bentonite Clay.
Bentonite is a natural clay product, which makes sheets that absorb water and other particles with ease. When dry Bentonite clay is mixed into a water-based slurry solution, carries a negative charge, which then bonds to the positively charged protein particles, to create a neutral compound, which sinks to the bottom of the tank.
The result is a clear wine on top, with a layer of thick, compacted clay-protein mixture on the bottom of the tank. From here, we can rack (or, gently remove) the clear wine off the top.
This step is usually only necessary for white wines and rosés—it’s harder to notice a protein haze in red wines.
Just one of the many steps that we do here at City Winery to get our wines ready so y’all can enjoy a bottle to-go!