Common Winemaking Considerations

Have you ever wondered what decisions go into winemaking to effect the result of what goes in your glass? Read on for a few of the more commonly known winemaking decisions that go into your favorite beverage. And if you are not familiar with basic winemaking techniques, check out my video (here on instagram) first.

Harvest Date

Probably the first and possibly the single most important decision the wine maker will make (unless they are also the vigneron and had to decide where to plant and how to train and whether to irrigate and... ) is when to harvest. 

Harvest too soon and the fruit will be overly acidic, vegetal and not fruity enough. It also won't have the sugars necessary to feed the yeast and produce sufficient levels of alcohol. Harvest too late and the opposite is true, the wine might be overly cooked in flavor with very high alcohol rendering the wine out of balance. This can largely be controlled for and determined by careful vine management and testing the fruit to determine best harvest date, however the winemaker can't predict the weather and will have to hedge based on likelihood of an early frost or rains or a sudden unexpected heat wave or … fires and smoke taint.  

Harvest is kicking off now in many parts of the northern hemisphere and will continue through until October. If you visit Napa or Sonoma Valleys these days you’re bound to see some signs of harvest. Though if you wait until daybreak to go looking, you’re likely to miss most of the excitement. Harvest usually takes place in the middle of the night in order to pick while grape sugar levels are stable and the conditions are better for workers. 

Fermentation Related Decisions

Wine is fermented grape juice. Grapes are harvested and crushed to break the skins and release the juice. Then yeast is added to kick off that fermentation process. Yeast can be one of many commercially available strains depending on the effect and action the winemaker is looking for, or it may be naturally occurring yeast. The yeast eat the sugar in the juice and produce C02 gas and alcohol as byproducts. When the yeast eats all the sugar, the result is a dry (not sweet) wine. When the level of alcohol that the yeast produce creeps above 15% that very same alcohol starts to kill the yeast. Hence it is rare to find a non-fortified wine much above 16% abv (alcohol by volume). Fermentation usually takes between 1-2 weeks. 

Maceration time

This refers to the length of time the skins are left in contact with the juices. The skins provide intense colors, flavors, tannins and structure for a wine. But left in contact too long and the wine might start to be overly tannic or bitter. Maceration time can be as short as a couple hours for a rose but may be as long as 50 days! 

Punch down vs Pump Overs

 

Punch down w/ the Winemaker

During skin-contact fermentation (for reds or orange wines cuz whites don't ferment with skins) the grape skins form a solid "cap" at the top of the fermentation vessel which has to be broken up. Breaking up the cap allows the skins to work their magic on the wine by imparting flavor, tannic "structure" and color. Winemakers use two techniques to break up the cap, sometimes both. Punching down involves pushing the skins down from the top with a large paddle-like device. Pump over is like the wine taking a shower with itself as wine is syphoned from the bottom of the tank and sprayed over the top. Pump over is a gentler process but introduces significantly more oxygen during the process. Winemakers may use both methods at different times even on the same wine to achieve their desired goals. 

Malolactic Conversion

Also called malolactic fermentation (MLF) takes place when bacteria convert the malic acid in the must (what we call juice turning to wine) into lactic acid. This is technically not a fermentation at all. It happens before, during or (more commonly) after alcoholic fermentation and can take 4-6 weeks. The result is a wine with creamier texture or "mouth feel" and buttery flavors, as well as more biologically stable. You notice the effect of "malo" often in those big "buttery" California Chards but the process is also used on nearly all red wines.

Lees Stirring

Lees is a euphemism for the dead yeast that sink to the bottom of the fermentation vessel after fermentation. They die from lack of food (sugar), age, or even when levels of alcohol get over 15% abv. Autolysis is a euphemism for self-digestion, it's what happens to the yeast as they die and then break down. You can see why we need a euphemism, right? But anyways, this process produces yeasty and biscuity flavors and some body in a wine. We refer to those flavors (similar to that fresh baked bread smell/flavor in champagne) as "autolytic" flavors. The flavors and textures are desirable in both red and white wine production to "round out" and tame some astringency. The lees must be stirred for several weeks to years to be effective. 

Malo and Lees stirring is not typically used in making more aromatic wines from Riesling, Viognier or Gewurztraminer. Those wines are usually celebrated for their floral and fruity flavors and winemakers don't want to overpower those flavors with oak, lees or Malo. 

Fermentation & Aging Vessels

Common aging and fermentation vessels include: stainless steel tanks, oak barrels, concrete eggs and amphorae (clay). 

Think of steel being at one end of the spectrum: it doesn’t impart any flavor or structure to the wine. It let’s the grape flavors speak for themselves unabated. 

On the other end of the spectrum is oak. When wine is fermented or aged in oak barrels the oak imparts

• Flavors & aromas of vanilla or coconut onto white wines

• Flavors & aromas of cloves, spice, cinnamon or smoke on red wines

• Barrels can be “toasted” or charred on the inside to accentuate some of the flavors 

• Because wood is porous some amount of gradual oxidation can happen during aging, resulting in some softening of astringency and increase of color and stability

• Oak also offers some additional tannins to the wine and some additional structure or mouth feel. 

If you think of the disparity of what oak and steel do to a wine, think of amphorae and concrete as being sort of a happy medium. They allow a slight amount of oxidation but impart very little in terms of flavors. 

Winemakers have to consider the effect each of these vessels is going to have on the wine both during fermentation and during any aging, they may use different types of vessels for different periods of time and for different parts of a blend. 

Bottling: Cork or Cap? 

The screw cap is the more perfect product. It preserves wine beautifully and as intended. Unlike natural cork, it isn't susceptible to cork taint or "TCA" which turns fruit flavors & aromas in your wine to something more like wet cardboard. Cork taint happens when fungus comes in contact with chlorine-based chemicals used in wood production. It affects 1-2% of wine bottles and isn't noticeable until after opening a bottle. Natural cork is also susceptible to drying out and shrinking, rendering the wine vulnerable to air and oxidation and premature aging and loss of yumminess. Those failures don't affect screw caps. 

While the screw cap might be the more perfect product there are 2 reasons I prefer cork. First, I love my Coravin, Coravin is another "perfect product" imho. It allows me to enjoy my wine bottle over months even years if I had that sort of self restraint. But alas it only works that superbly with natural cork closures. The screw cap attachment, while a delightful & welcome innovation is only adept at keeping that wine preserved for weeks. I also love the ritual of cutting the capsule on the bottle, screwing the opener into the cork and removing it. There is just something slightly romantic (if not suggestive?) about that process. A screw cap is just too modern and new for me and the wine industry traditionalists that frown upon them.

Hope you enjoyed this installment of winemaking considerations! If you’d like to learn more and get more frequent updates, please follow me on Instagram too!