What’s In My Wine? Part 1: Protein Stability and Bentonite Fining

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.


Protein haze in wine on the left, clear wine on the right


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.


Realistic representation of the chemical reaction happening inside the tank.


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.


Mixing bentonite clay into a slurry solution



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.



Clear wine separating out from the bentonite in a glass Carboy

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!

Join us on our Gorgeous City Winery Patio for #WineWednesday

Come join us for #WineWednesday on the Patio, the weather is going to be gorgeous and we are celebrating the first week of Spring with some Wine and Beer Specials!
Bubbles $5/gl
Korbel, California
Perelada Brut Cava, Spain

Rose $5/gl
Latue, La Mancha, Spain
Chapoutier Belleruche, Cotes du Rhone, France

Domestic $4
Coors Lite

Craft $5
Napa Smith Amber Ale
Sierra Nevada Nooner Pilsner
Sierra Nevada Torpedo Extra IPA
Sierra Nevada Hop Hunter
Sierra Nevada Stout
Abita Grapefruit Harvest IPA
Southern Prohibition Brewery Suzy B Blonde Ale
Crazy Mountain Lawyers, Guns, & Money

Also, Wednesday is Buy One Get One 50% Off of any of our retail wines! You may pick up retail bottles at the concierge desk or ask your sommelier, server, or bartender for more information. We are open 11am-2pm for Lunch, & re-open for Dinner 5pm-10pm. Stop by and see us!

Easter Brunch

City Winery Nashville will feature an Easter Brunch on Sunday March 27th. The barrel room restaurant will offer a buffet for $25.00 for adults and $10.00 for children 12 and under. In the venue, Rock and Roll Gospel Revival Easter Brunch will be held for $40.00 a person. Your ticket price will include an Easter buffet and music from some of Nashville’s best singers and players, including Bonnie Bishop and many more special guests. Easter Brunch Buffet Menu


This Week in the Winery: Rack & Roll!

By Laura Cypress, Asst. Winemaker
This week in the winery, we’re racking our 2015 Chardonnay, the first of our 2015 wines made right here in our urban winery in Downtown Nashville. The Chardonnay comes to us from Scopus Vineyards in Sonoma, California, a vineyard atop Sonoma Mountain. We’ve been lucky to work with this vineyard for several years, which is special, as we can compare our Scopus Vineyard Chardonnay across several vintages, and made by several winemakers (Including David LeComte at City Winery New York, Robert Kowal at City Winery Chicago, and Bill Anton here in Nashville.)


Barrels about to be racked

Racking is a process in winemaking where we remove all of the clean wine off of a layer of lees, which are dead yeast cells and sediment that sink to the bottom of a tank or barrel. Many barrel-aged wines will be aged Sur Lie, or ‘On the Lees,” because the lees contribute a good amount of mouth feel and complexity to the wine as it ages in barrel. Typically, we like having lees in our barrels—we even stir the lees up once a week in our Chardonnay and Pinot noir barrels, to encourage more interaction between the lees and the wine. We rack the clear wine off the lees when we feel the lees have contributed enough to the wine, and we’re ready to prepare the wine for bottling.


We rack the barrels using a ‘Bulldog Pump.” It’s a gentler pump, which uses nitrogen to pressurize the barrel and gently push the wine through a hose, to the tank. We slowly lower the wand down into the barrel, while watching the sight glass so we know we’re only taking out the clear, clean wine (and not the creamy, opaque lees at the bottom.) All of the wine in these barrels is being amassed in a stainless steel tank, to create our final blend. After mixing all twelve barrels together in the tank, we re-filled one oak barrel with the blend, so we can evaluate how this wine continues to age in barrel.


After racking our barrels to tank, we had about 18 gallons of lees that we collected from the bottom of the barrels. These lees can range in consistency from a thick custard-like texture to a thinner, milky texture. You know you have healthy lees that are helping your wine when your lees smell fruity, floral, and taste fresh. We emptied these lees from the bottom of our barrels, collected them, and we’ll let them settle out in glass carboys for a week or so, to rack any additional wine off the top. After that, we’ll put them in containers and give them to the kitchen to add to our delicious flatbread dough!! (It’s the lees that make it so good!)


Collecting lees in a glass carboy

But how do you clean these messy, lees-y barrels? Using the MOOG!!! This special barrel-washing device connects to our pressure washer, and uses rotating heads of high-pressure water to clean the debris, yeast, and tartaric acid crystals out of our barrels. It also simultaneously suctions all of our cleaning water out of the bottom of the barrel. These white wine barrels will be used next year for more Chardonnay.


Pressure washing each barrel to clean it

Now that all of our 2015 Chardonnay have been blended in tank, we still have a couple of steps to take before this wine can be kegged and bottled for you to take home, including cold stability and protein stability. Stay tuned to learn more about these processes to help get Downtown Nashville’s first wines on your dinner table! For questions on winemaking, email Laura Cypress at laura@citywinery.com.

Read All About Garth Brooks Singing the Worst Song He Ever Wrote at City Winery


Garth proved that not all songs are winners at the second annual “The First and the Worst,” a fundraiser for the Music Health Alliance held at City Winery, Tuesday, March 1. Brooks, along with talented singer-songwriters Lee Brice, Jessi Alexander and Bobby Braddock, were all tasked with playing the worst song they’d ever written as well as the first.


You can read all about the fantastic night in Rolling Stone, The Tennessean, and Wide Open Country.