Preparations

Some preparations are made before the crush begins. Tractors and trucks are checked. Clippers, tote bins and plastic buckets are acquired, if necessary. Winery equipment is checked and thoroughly cleaned. Bottling line and the Carlsen pump (positive displacement) can be deferred to winter. Barrels are cleaned and repaired.

Then, even after the picking begins, the needed supply of chemicals and yeasts is laid in. As many as half a dozen strains of yeast may be needed, most in freeze-dried form, the rest as liquid cultures. There are: malo-lactic bacterial cultures, tartaric and citric acids in granular form, and sugar; yeast nutrients DAP (diammonium phosphate), yeast hulls, and/or proprietary mixes; enzymes to aid extraction; sulphur dioxide in granular (potassium metabisulphite) or liquid form; argon, nitrogen, carbon dioxide and oxygen gasses; laboratory test materials for residual sugar, malo-lactic fermentation progress, and free sulphur dioxide; propylene glycol for the chiller; barrels; cleaners for the floors and drains, and for the tanks, hoses and pumps; filter pads. Equipment for fighting the birds also requires servicing.

Some control measures may be needed to reduce the yellow jacket population.

Determining ripeness

Let’s begin with the timing of harvest. The winemaker will track development of sugar using a refractometer in the vineyard. This handy device bases the percent sugar content by weight, in degrees Brix, on the diffraction of light through the juice. All it takes is one drop of juice to obtain a reading.

When the sugar reaches a threshold level, it is time to begin collecting sample clusters for lab analysis. Three or four clusters are picked and taken to the lab. The juice is then analyzed for sugar (degrees Brix), titratable acidity (grams/liter) and pH. The figures are recorded and plotted on graph paper to enable projection of the harvest date. The winemaker follows this data and, when a certain point is reached, many order picking to begin. The best winemakers head for the vineyard and sample for aroma and taste directly before deciding. The numbers are used to get in the ballpark; actual sensory evaluation is the most important indicator of ripeness.

Picking

Picking begins, but labor negotiations may not be settled yet. Sometimes, pickers will drop their clippers and walk off, demanding an upward revision of compensation. They are paid by the 5-gallon bucket or flat. When they see the cluster size and other factors relating to picking difficulty, they figure out quickly whether they have a good deal or not. There can be a big difference between, say, 1-pound Chenin Blanc clusters and those of  Gewürztraminer, which run about 8 clusters/pound and the stems wrap around things like they can’t tell they’re not tendrils.

It is best to pick when the fruit is cold, probably in the early morning depending on the weather. If the grapes are warm when pressed, too many harsh compounds will be extracted from the skins, seeds and stems, reducing the wine’s quality. Too many grapes will crush in the picking bin, losing valuable juice.

Cool weather enables a longer picking day. Larger wineries may have a refrigerated building where they can put the afternoon picking for cooling. That fruit can be crushed in the evening. But it‘s still not good to pick warm fruit say, when it‘s 95°F outside.

Domaine Chandon (Napa Valley) determined that machine picking at night yielded just as high a quality level for making sparkling wines as hand picking in the early morning. So, they pick by machine during the night under the glare of large floodlights.

At the crush pad

Even before destemming, some wineries run the clusters across a flat conveyor belt, with workers on both sides eliminating moldy clusters and grapes.

The next encounter for the grapes is with the destemmer-crusher. This stainless steel marvel separates the grapes from the stems. First, the grapes drop into a revolving cylinder that is punched full of holes. Inside of it, there is a counter-rotating shaft with paddles. The holes are designed so that they separate the grapes from the stems without breakage. The stems eject from the end of the cylinder and into a collection bin.

The whole grapes drop down to the crusher rollers. On good machines, the distance between rollers is adjustable, so different sizes of grapes may be accommodated or, in the extreme, the grapes pass through with none crushed.

The resulting mass is pumped to the press by a piston pump or an “Italian ferris wheel,” (peristaltic pump).

For sparkling wine production, where the wine is very sensitive to uptake of harsh, bitter constituents, whole grape clusters are loaded into the press manually.

Pressing

Stainless steel presses called “membrane press” or “tank press,’ are the preferred equipment for separating the juice. Both types utilize a rubber-impregnated canvas membrane, and the pressure is applied by compressed air.

If the grapes/juice are cold, some skin contact can be conducted in the press. Just leave the mass sit there for 1-4 hours without starting the press. It should not be done with warm juice, because harsh and bitter compounds will surely be extracted and there is a risk of spontaneous fermentation occurring in the press. It also ties up the press. To keep the press working, it may be necessary to install a refrigerated tank on the crush pad, specially designed to accommodate the pumping of juice, skins and seeds.

Modern presses have built-in computer control programs with as many as to 10-12 standard pressing routines. The winemaker can select one of those, or specify his own procedure. Typically, the press starts with 4-6 squeezes at 0.2 atmospheres pressure (6 psi). In between, the compressed air is evacuated, and the tank rotates to mix up the mass. This is real gentle pressing, and up to 80% of the juice may be coaxed out at this low pressure without picking up those harsh substances from the seeds and skins.

Next, the pressure is increased in steps, with rotation in between. The ending pressure is typically 3 atmospheres (~45 psi)

Juice drops into a juice pan and is pumped to a tank for settling. Many wineries wish to increase quality by routing the free run juice and first few squeezes into one tank. Some winemakers taste the juice right out of the juice pan to determine when to stop this prime, or free-run fraction. The rest of the juice is shunted to another tank where it will settle and be fined or filtered to remove harsh components. Quality of the juice decreases with each successive squeeze, because the juice closest to the seeds within the grape is the lowest in sugar and highest in acid and tannins. Fining can reduce the quality further by stripping flavor and aroma. Ultimately, some of the press fraction may be buried in the generic table wine.

Red wines are handled differently. Fermentation will be conducted in contact with the grape solids, maybe even some selected whole clusters. The clusters pass through the destemmer-crusher to remove the stems, and the grapes pumped to the fermentation tank. “To crush or not to crush, that is the question.” Typically, most red grapes are crushed. For top quality Pinot Noir, however, an effort is made to keep as many berries as possible in the uncrushed condition going into fermentation.

Even though most are whole grapes, there is some breakage and juicing. The mass, now called must, can be moved to the press by a pommace pump.

The best destemmer-crushers and presses are made in Germany and Italy. There are a couple of very good makers in France and Switzerland, too.

Saignée

Literally translated, saigneé means to bleed. If the winemaker wishes to increase the ratio between skin area and juice volume, thus increasing the wine’s intensity, he/she will draw off some free-run juice at this time, typically 10-15% of the total juice volume. This juice is then made into a rosé wine.

Cold soak

In production of top quality red wines, it has become fashionable to let the juice, seeds and skins macerate for 4-8 days after cooling them to ~48°F and blanketing them with CO₂. During this period, the juice extracts color, aroma and flavor constituents from the solids without dissolving tannins. The extraction of tannins is dependent on the presence of alcohol, and there isn’t any yet.

Fermentation

Fermentation activities begin when that first batch has been pressed, settled and racked. About 3% suspended solids is generally acceptable going into fermentation, even considered desirable for complexity some varieties. DE filtration (diatomaceous earth) or cross-flow filtration may be needed to clean up the slop at the tank bottom (juice lees) after the racking.

In anticipation, the winemaker makes a yeast starter culture. If you follow California practices, you will just add lots of freeze-dried yeast to the juice. That’s expensive. I prefer to make starter cultures using frozen apple juice or some clean juice. Same freeze-dried yeast, but very little of it is needed this way.

Chardonnay, part or all, may be loaded into 225-liter barrels for fermentation. Pinot Gris or Sauvignon Blanc may go into 500-liter puncheons.

The must is on is way to becoming wine. Temperatures vary by variety: 54-55°F for aromatic varieties like White Riesling, 60-62°F (in-barrel is warmer) for Chardonnay, One day at 86°F for reds, then drop to a maximum of 80°F for the duration. There are differing opinions on these. All the winemaker has to do now is track the progress, identify any problems that may be developing and take corrective action immediately.

Red wines are fermented in open-top fermentors. They need to be punched down or pumped over 3-4 times a day, depending on how rapidly the yeast is working. There is a new process, called Ganimede^©, that uses the CO₂ generated by fermentation to roll the cap. Care is needed so as to not blow off the aromatic constituents for the sake of labor savings.

Work load

Picking, crushing, pressing and fermenting can be simple for a small winery making, say, two wines. Once a winery gets up to about 50,000 gallons in size (330 tons), the number of batches can grow to as many as 40 or more. For sparkling wines, the number of batches is much greater because the juice is separated into press fractions for fermentation. It is standard for winemakers in Champagne to divide the pressed juice for a single press load into 13 fractions. American operations are not quite so persnickety. 4-5 fractions may be sufficient. But, source vineyards are also kept separated. It can be a nightmare.

All of these processing batches require tanks, barrels and record keeping. Just think of the complexity of managing all of these lots through the fermentations that follow, and you will have some idea of how complicated wine production can be.

Staff work load

In a small winery, the winemaker has to do everything. There are usually a small number of batches to deal with. In a larger winery, let’s say over 15,000 gallons (which is still pretty small), the number of batches coupled with the time required to process each of them, assistance will be required. Here is an opportunity for winemaking students and recent graduates to gain some valuable experience. These jobs typically are temporary, about 3 months in duration. The upscale job title is “intern.” To the old hands, these part-time helpers are known as “grunts” or “cellar rats.”

It is not unusual for the winemaker to work 7 am to 10 pm days during the crush. That’s 15 hours per day, including some weekends for almost two months. The price paid for making outstanding wine is high. He/she may keep a cot and/or air mattress at the winery. Some lucky ones have a separate building with a “crash pad” with a real bed and shower, at the winery. Comp time off? What’s that? I don’t think winemakers ever get to average out to a 40-hour week . . . not when you consider all of the after-hours time worked at charity events and winemaker dinners.

The crush is grueling. You really have to love it to go through the experience year-after-year. Why do they do it? The reason probably lies in the challenge of making a product from the ground to the bottle, and then have one’s name attached to the result. Real winemakers regret that they only have 30-40 opportunities to do it.

Winery visitors

The crush is a great time to visit a winery, and many people do it. The smell of fermenting wine is very appealing. It’s fall, and the weather can be terrific. Pickers are busy in the vineyard. Tote bins full of beautiful grapes arrive at the crush pad. If you’re lucky, you can taste the fruit at the zenith of its ripeness. Couple all of this with a few snaps in the tasting room, and you might have a euphoric experience.

Even if you’ve been there before, it’s always fun to take a winery tour. The task is made more difficult than usual by wine hoses on the floor. Spilled juice can be very slippery. If the winemaker is injecting sulphur dioxide into the juice for protection against micro-organisms, the smell can be irritating.

Visitors place an extra burden on the winemaking staff that is already fully employed making wine. So, it is essential that wineries have a separate tasting room staff to carry the taste and tour burden.

This discussion may help you understand why winemakers may not be pleased to see you during the crush. They’re probably exhausted and mentally engaged in more important things.  Deep down, though, they know they need you. They’ll be real happy to see you the next time.