Ok, here we are at the last of the Learn About White Wine Production series. If you missed the other posts, we talked about crushing and pressing the grape clusters, prepping and settling the wine must, acidification and chaptalization. Then we went into primary and secondary fermentation, racking, sur lie aging, Bâttonage, and sulfur adjustment
And now The Clarification Process Of White Wine Production.
While racking helps remove suspended particles by the simple act of gravity, some finer matter still remains in the wine and must be removed via centrifuging, filtering and fining.
Assuming you know what centrifugal force is, centrifuging separates substances by spinning it at high speeds. Any remaining matter in the wine is quickly removed this way. The down side of centrifuging is you lose flavor compounds of the same density as the matter you removed.
You can figure out what filtering is. Think coffee. This can remove even the smallest particles like bacteria.
Now fining works completely differently but achieves the same effect. A fining agent is added to the wine which then sticks to particles that were unable to be removed in other ways. Once bound to the fining agent the particles are then too heavy to remain and thus sink to the bottom. Then the wine goes through the racking process.
Below are a list of the Common Fining Agents used:
- Gelatin: removes excessive tannin
- Egg white: removes excessive tannin
- Tannin: removes protein
- Bentonite: removes protein
- Casein: removes acids and tannins
Heat and Cold Stabilization
Suspended proteins not removed from a white wine can form a white haze if the wine is exposed to heat. To prevent this, fining agents like tannin and bentonite can remove those suspended proteins before the wine goes to bottling. This process is called heat stabilizing.
Barrel-aged wines can heat stabilize naturally due to the fact that oak tannins from the barrel itself combine with suspended proteins and precipitate out.
When a white wine is chilled crystals form. These tartaric acid crystals can look like snowflakes or glass shards in the wine, but they are harmless. Typically wines are cold stabilized two to four weeks in fermentation tanks so that the precipitate stays there.
Aging, Blending, and, finally, Bottling
If a white wine is intended to be aged it is usually done in oak barrels. Stainless steel doesn’t impart any flavor or allow the oxidative process that happens in wooden casks. Barrel aging adds complexity by softening tannins and adding flavor.
A barrel can also help marry a blended wine by giving the various components an environment to knit together as they age together.
While many wines are varietally labeled, up to 25% of other grapes may be added for complexity without having to be named on the label. Blends offer wider displays of aromas, flavors and textures to a wine. A blended wine can either mixed before aging or are aged separately and then blended before bottling.
And finally, when the white wine is stable and ready to hit the stores, it is bottled. This is more than likely an automated process that fills the bottles and places the cork in the neck.
That concludes this series on white wine production. I’m glad I could help you learn about wine and some of the exciting moments in its production. Our next series will be on red wine production. Until then…