Monday, November 22, 2010

Yeast: Part I of XVI

During my time at the winery, I've written about most every step in the winemaking process except for the following:

- Adding yeast & nutrients for primary fermentation
- Malolactic (secondary) fermentation
- Fining and filtering (the steps that precede bottling)
- Blending
- Bottling

If there's one step that's more critical than all others, I'd have to say that it's adding yeast. Unfortunately, it's something that I didn't witness very often. We typically started working at 8:00 am, but the winemaker often added yeast and nutrients to the fermenting must around 7:00 am.

The process is not too complicated, but many things can go wrong. First, a package or bottle of dried yeast is mixed with warm water. The resulting mixture looks like a giant latte (coffee + milk colored, opaque) and smells like baking bread. There are different types of yeast, and choosing the right one(s) is what makes great winemakers great. We typically fermented different bins with different strains of yeast to obtain varying characteristics in the wine.

Syrah yeast.  There are hundreds of different types of yeast that can be used
to ferment must into wine.  We used about a dozen varieties this year.

The liquid yeast is poured into the tanks and bins, and this procedure is called "inoculation". The yeast cells then process the sugars in the must into CO2 and alcohol. And herein lies the difficulty in making wine: As the level of alcohol rises, it kills the yeast. As the sugar gets depleted, the yeast cells run out of food. If the temperature rises too much, the yeast dies. If the temperature is not high enough, the yeast doesn't process the sugar. If the pH isn't just right, the fermentation can be affected. And so on... It's a pretty delicate process, and getting it right isn't so easy.

The amount of alcohol that is produced by the yeast is directly proportional to the sugar content of the must, and since we crushed very ripe grapes we often had to add water to dilute the must. Too much sugar will create too much alcohol, which will kill the yeast before the fermentation is complete (but we have a secret weapon to fix this problem). Sometimes, the fermentation can be re-started once the wine has been transferred to barrels:

The master adds a little bit of WS yeast to some barrels of wine that are
still a little too sweet. This yeast will ferment the remaining sugar and
dry out the wine. It's not the preferred way to do things,
but sometimes you don't have much of a choice...

I'll post a few more things about yeast, most notably a little something about some very special yeast that we use in desperate cases. Stay tuned...

Saturday, November 13, 2010

"Smoked wild game, herbs de Provence and hints of bitter Swiss chocolate"

If you've ever read some of Robert Parker's wine reviews, you've probably laughed out loud at some of his descriptions. He'll routinely toss in words like "graphite", "roasted meats", "bacon fat", "wet slate", or "cedar" and "spicebox".

But what words would you use to describe the flavors in your wine?  Here's a handy little illustration of a flavor wheel.  It'll help you figure out what basic flavors you're tasting when you're swishing that wine around in your mouth:

Here's a handy wine "aroma wheel" to help you decipher some of the
flavors present in your wine (click for larger image)

If you're making wine, you obviously don't want to find yourself anywhere near the "chemical" section of the flavor wheel, nor do you want your wine to taste like yoghurt. Floral, spicy, or fruity flavors are great, though, and there's a trend toward more herbaceous flavors like hay, herbs, and menthol/licorice.
Print out the wheel and take it with you when you're wine tasting!

Tuesday, November 9, 2010

Slightly Less Fun than a Barrel of Monkeys

Much of the past 2 weeks has been spent barreling. We've been digging out tanks, pouring out bins, pressing the skins, and putting lots of delicious wine into oak barrels.

The process consists of cleaning out used barrels, prepping new barrels, and then filling them with wine from the press. Since we store old barrels wet, we need to clean them out with the barrel washing tool (see post from October 19 - "Cleaning Barrels and Tanks") and then rinse them with ozonated water:

A 228 liter (60 US gallon) barrel weighs about 550 lbs (1 liter = 1 kg, or 2.2 lbs, plus the weight of the barrel). That makes it very difficult to move a full barrel, so to ensure that each barrel's interior is completely ozonated, we fill them one quarter of the way and roll them on their racks:

For new barrels, we rip off the plastic covering and remove the temporary bung. A brand new French barrel will cost you about $1200 - $1400, so most wineries do not age their wines in 100% new barrels.  Besides, it would give the wine too much oak. So unless you work at Chateau Figeac ( you use a mix of new and old barrels.

Then it's time to fill 'em. We pump the wine from the press (see post from October 18 - "Stop the Presses") into the barrels using a handy barrel filling tool:

The barrel filling tool is simply a stainless steel pipe with a right-angle
bend and a little glass window (to see if wine in flowing)
The small glass window at the center of this picture allows you to see if
wine is flowing into the barrel.  Since it's dark in the barrel, it's really
hard to see if it's filling properly

Wine barrels are typically toasted on the inside. That means that the barrel makers purposely char the wood to give the wine a smoky, "oakey" flavor. It smells amazing! Unfortunately, that also makes the inside of the barrel very black. And since wine is dark red, it's quite difficult to see what's going on when filling barrels. Here you can see our assistant winemaker use a flashlight to gauge the level of wine in the barrel:

Once the barrel is full of wine, we put a special bung in the barrel's bung hole. It's a rubber bung with a hole through it, and the hole is plugged with a plastic fermentation lock. A ferm lock is a small version of the pipes under your kitchen sink, and it keeps air from flowing into the barrel while also allowing gas to escape as the wine continues to ferment. You can see it in action below:

Here's a little more info on barrels: We use at least 4 different sizes of barrels, and almost 100% are French oak. The standard size is 228 liters, or 60 gallons. That will fill 25 cases of bottles (25 cases X 12 bottles X 0.75 liters/bottle = 225 liters).

We also use 114 and 500 liter barrels. When full, they weigh 290 lbs and approximately 1200 lbs, respectively. Our largest barrel holds 2500 liters. No, that's not a typo. The larger the barrel, the less oak flavor will be imparted to the wine.

Barrels also come from different forests, so different manufacturers are used for different characteristics. It's quite common for our winemaker to choose different barrels for the same wine. He'll blend them before bottling to obtain desired characteristics.

A regular 228 liter barrel from Seguin Moreau with Medium Light Toast
(MLT designation on the face of the barrel)

Now that you know how much wine fits into a small barrel, and how much it weighs, you'll get a good laugh at this silly commercial for Jameson's Irish Whiskey:

Friday, November 5, 2010

Visit to a Contract Winery

A couple of days ago I took a quick trip to Napa to visit a friend's contract winery. John Wilkinson is the managing partner at Bin to Bottle, a large operation that makes wines for a bunch of super premium brands in Northern California. When I last saw John two years ago, he was putting the finishing touches on his barrel room:

Bin to Bottle's [relatively] new barrel room.  It's about the size of a football field,
and it's packed 6 barrels high!

Since most of his clients age their wines in barrels for 1 to 2 years, he keeps them in a fully climate-controlled room at 75% humidity. And since Napa gets really hot during the summer, the entire roof of the barrel room is covered with state of the art solar panels that provide 100% of the facility's AC and lighting needs. At night, once the outside air gets cool enough, large vents automatically open up to ventilate the facility and cool it without any need for additional power consumption.

BTB has about 200 fermentation tanks, and most are stacked tanks (2 tanks, one on top of the other). Here's what a couple of rows of tanks look like:

Stacked fermentation tanks with glycol cooling lines.  The main glycol
lines run along catwalks suspended from the ceiling, and individual
lines run down to the tanks.  This arrangement leaves the floor
completely clean of any pipes or lines -- thereby avoiding injuries
and cleaning problems.  Smart!

On a big day, BTB will receive, sort, crush, and pump about 200 tons of fruit into ferm tanks and/or fermentation bins. On a big day, we (meaning the winery where I am working) will do less than 20 tons!

Thursday, November 4, 2010

Digging in the Dirt

With all due respect to Peter Gabriel and his groundbreaking 1992 video (watch here:, I doubt that he ever had to dig out a fermentation tank.

Once the fermentation process has ended, it's time to drain the wine out of the tank and then press the remaining skins that have risen to the top of the liquid. The "free run" (aka "free flow") wine is drained from the bottom valve and pumped into barrels or another holding tank. Pumping into another tank is called "racking" and it helps remove the lees, or dead yeast cells, from the wine. Watch the free run wine gush out of this tank:

After the majority of the wine has been drained, we open the tank's door and dig out all the skins. We put them in bins and then squeeze them in the press. The press runs through a sequence of pressings that increase in intensity, and that means that we end up with 3 types of wine:  free run, light press, and heavy press. Free run makes the best wine, while heavy press makes the least desirable (more on this topic later).
This is what the grape skins & seeds look like after fermentation

A tank is considered a "confined space" by OSHA, so we have to follow certain safety rules when entering.  This is why I had to put on a safety harness and ensure that one of my coworkers was present at all times (presumably to rescue me if I were to pass out):

A safety harness that looks like a parachute harness,
and a bucket of ozonated water (sanitizer) for my feet

At work in the tank...

These grape skins were surprisingly cold! Even though this particular tank reached a peak temperature of roughly 90°F (32°C), by the time I got in to scoop out the skins the temperature had fallen back to about 63°F (17°C).

Monday, November 1, 2010

Handy Flow Chart

Some people have asked me for a summary of the winemaking process, so I've put together a pretty basic flowchart that illustrates the major steps (click on image for larger size):

This flowchart summarizes the winemaking process for
grapes with high sugar content.  For cooler grape
growing regions, the process is slightly different

NOTE:  This is a general flowchart, so before sending me hatemail with comments such as "sometimes you DO de-stem white grapes, dumbass!" let me clarify a few things:

1 - This flowchart is for warm growing regions (such as California, Southern France, Australia, etc.). For cooler regions (Finger Lakes in NY, Germany, Canada) the process may be different. Instead of adding water, for example, winemakers may need to add sugar.

2 - While white grapes are often pressed without de-stemming, some grape varietals require different processes. Still, most while grapes are pressed immediately and the skins are discarded. Only the juice is used to make wine. Red wines, however, require that the juice and skins stay in contact for a long period of time.

3 - Some winemakers don't add yeast to ferment their grapes. They use "native fermentation" and the yeast that develops in the must is naturally-occuring. We use yeast and I will discuss the many steps involved in that process in future posts.
4 - The flowchart is simplified and some steps are purposely missing.  For example, addition of SO2, addition of nutrients during fermentation, fining and filtering before bottling, blending before bottling, etc.