The Life Cycle of a Grape

How to make wine – this is a super interesting process which I think all wine drinkers should get to know.  Whether you LOVE wine and have become a self-proclaimed oenophile or are just the occasional have a glass with dinner type of wine enjoyer, understanding the journey of how your beverage made it to your glass is an important one.

Because we’re located in the Napa Valley I’ll be referencing some local highlights regarding the wine region, but the post will be all encompassing in terms of the winemaking process and life cycle of a grape from start to finish.

So, without making this intro too lengthy since we have a lot to cover, let’s get to it!

PLANTING

We’re starting from the ground up, literally!  Imagine, you’re lucky enough to have just acquired land in a grape growing region.  For the purposes of our story, why don’t we say you’ve come in to some land in the Napa Valley.  You have a bare patch of land and need to assess the climate and soil type to determine which grape varietals will thrive on your new property.

In Napa Valley, Cabernet Sauvignon is king, but that’s not the case everywhere.  Different microclimates or AVA’s (American Viticultural Areas) for us Americans, lend themselves better to different grapes.  Napa itself is considered an AVA, established in 1981 as California’s first AVA.  However, there are 16 sub AVA’s within the Napa Valley with differing climates and soils.

Warmer temperatures and rocky, volcanic soils are ideal for growing Cabernet.  Where cooler microclimates and sandier soils are preferred for Sauvignon Blanc.

It may benefit you and your newly acquired land to seek the knowledge of a vineyard manager, who might suggest planting small amounts of several grapes for blending.  Some Cabernet Sauvignon wines are made up of a combination of Petit Verdot, Malbec, Cabernet Franc, and/or Merlot in addition to the Cabernet Sauvignon.  Others, such as First Avenue Vineyards, are 100% one varietal (Cabernet Sauvignon).

You’ll also want to consult your vineyard manager on the best site for your new vineyard(s), if amending the soil is necessary, how to space and eventually trellis the vines, and orient the rows.

Orientation of the grapevines is important.  As with most plants, grapevines need sunlight to produce and ripen quality fruit.  Typically, vines are planted so the rows are facing north and south to allow them the most sun throughout the day.

Then it’s time to plant.  Usually you’ll pick out a clone of a vine like Cabernet clone 337 for example and plant the baby vines in your whole vineyard.  Once the baby vines are planted usually, you’ll place a carton around them to protect them from the cold while they’re so small.

Here’s the part that takes some patience… Waiting for the first harvest.  You’ll take extreme care over your vineyard for the next several years.  Yes, I said several.  Lots of care, close attention, watering, proper pruning, and protection from disease and harmful pests.

PRUNING

By now you have been patient for approximately 3 long years.  This is the year your vineyard will finally produce a harvest!  It’s still Winter and the vines are dormant, bare, with no leaves.  The roots are deep in the soil feeding on the nutrients it takes to produce fruit.

When the vines are dormant in the Winter it is time to prune.  Pruning is actually essential to a healthy, premium grape crop and must be done properly.  Proper pruning skills are prized here in the Napa Valley.  Each year, Napa Valley Grape Growers hold an Annual Napa County Pruning Contest in February which is a sponsored event.  There is a men’s and women’s division where both accuracy and speed are judged.  Cash prizes and special personalized belt buckles are won if placed high enough.  The 2020 turn out was 160 contestants total.

The goal is to achieve the proper ratio of shoots to buds, which will eventually produce the grapes on the vine.  If there are too many shoots and not enough buds the vine will have too many leaves shading the grapes, and the fruit will have a tough time ripening.  If there are too many buds and too few shoots there will be too many grapes, but the grapes won’t ripen well because of the quantity.  Poorly pruned vines result in poor quality fruit.  Without premium quality fruit, a winemaker can’t produce premium wines.

BUD BREAK

We’re into early Spring now, and in the Napa Valley that’s usually about the time all the pretty yellow mustard flowers are blooming in the vineyards.  It’s a gorgeous time to visit!

The first buds appear on what used to be the dormant vines, hence the name “bud break”, and usually begins in March.  Days are usually mild and dry, but nights can be very cold.  Vineyard managers will keep a watchful eye on nighttime temperatures as they can dip below freezing which can cause serious damage to the buds on the vines.

FLOWERING

The flowering stage occurs about a month after bud break.  The vine will develop tiny clusters of flowers.  Each flower having the opportunity to turn into a berry.  So, to protect this extremely delicate process from those extremely cold nights, huge fans are used to circulate air keeping the cold air from damaging the vines.  You can imagine how loud these fans are!  If you live anywhere near a vineyard it’ll sound like a plane is taking off in the middle of the night right outside your window.  But a necessary plane if you want your crop to survive.  Sometimes heaters are used to warm the air temperature as well.

Alternatively, some vineyards use sprinklers to coat the vines in a protective layer of ice.  This seems like exactly what they’re trying to avoid, right?  It’s actually science!  Believe it or not, the freezing process of the sprinkler water icing over on the vines produces some heat.

In the Napa Valley, the flowering stage can last over a period of about 2 months because of the variance of all the different microclimates.  There can be a 10˚ F difference from cooler AVA’s such as Carneros to the Calistoga AVA.

FRUIT SET

Usually in May, the pollinated flowers will begin to shed their petals.  What’s left will be small bright green berries at the end of the stems where the flowers once were.  Once the fruit is set, it will slowly begin it’s ripening process.  However, not all vines will self-pollinate.  So, if many of your vines are still showing flowers and no fruit clusters as the month goes on, this will be firm indicator that your crop yield will be low.  In the Napa Valley where Cabernet Sauvignon is king, this can mean a major hit to your pocket book.  In 2019, the average base price per ton for Cabernet grapes in Napa County was $7,942.93 according to the USDA.

CANOPY MANAGEMENT

This is also the time that vineyard crews will begin “leafing”, which is the term used to explain canopy management in the wine business.  Canopy management is another important aspect in regard to crop abundance and quality.  Grapes need sunlight and air to ripen, but too much sunlight and the fruit can actually sunburn.  So, a controlled amount of both these in is crucial in premium grapes clusters.

CROP THINNING

At this time, crews will also inspect the fruit clusters themselves and cut away any that aren’t developing properly.  For an owner or a grower this can be painful to see so much fruit drop, but the crop thinning helps the vines put energy into only the highest quality, top dollar clusters of fruit.  The Napa Valley actually produces only about half the fruit per acre compared to other grape growing regions.  The Napa Valley price per ton is also about 5 – 6 times what the average California price per ton is.

VERAISON

Typically, late July or early August is when you’ll start to see the veraison process start.  This is in my opinion, the most magical and exciting part of the Life Cycle of a Grape!  Veraison is when the grapes begin to change color.  So, if you’re growing a red varietal like Cabernet Sauvignon the bright green clusters will begin to noticeably change purple.  Sauvignon Blanc or Chardonnay grapes will begin to turn more translucent and have more of a golden-green hue, edging further away from that harsh bright green color.

This change in color is nature’s way of telling us that the grapes are ripening and developing sugars.  Napa has a climate very much similar to that of the Mediterranean climate which makes it ideal for growing grapes and making excellent wine.  These Summer days are hot and sunny, but the nights are cool.  The swing of degrees in Fahrenheit can be anywhere from 30 – 40˚.  So, the daytime heat promotes sugars and ripening, and the cooler temperatures in the night allow the grapes some restraint and structure, keeping their acidity.  This equates to some phenomenally well-balanced wines in the long run!

HARVEST

Can you believe you’re finally at the harvesting stage?!  Winemakers know how to pick by measuring the sugar levels in the grapes called Brix (˚Bx).  This is a way to measure the potential alcohol level a wine will have before making it.  Every winemaker will have their own opinion of course of the optimal level.  In the vineyards, winemakers can use what’s called a refractometer which tests the sugar levels of a single grape to know which sections of the vineyard are ripening first, therefore knowing which blocks to pick first.

When it’s close to harvest winemakers are watching weather by the minute!  A few hot days can push a vineyard into harvest, and a few cooler days can delay the harvest date.

As with food pairings and tasting wines, ripening grapes follow a similar order.  Sparkling wines are harvested earliest because there is a low sugar content desired for them.  It’s been known that sparkling wines have been harvested as early as late July!  Followed by white wines like Sauvignon Blanc and Chardonnay in late August, early September.  Malbec, Pinot Noir, and Merlot typically follow.  Finally, you have your big reds like Cabernet Sauvignon in October and as late as early November.  If you’re in the business of making sweet or dessert wines you could be harvesting as late as December.

Vineyard crews are usually harvesting when it’s dark out with big lights to light the vineyards.  Normally at about 3:00 AM, when the air is cool and they can get the grapes to the crush pad before fermentation would begin in the warmer part of the day.

Congrats!  It’s been 3 years and you’ve finally harvested your first crop from your vineyard off what used to be your new stretch of land.  But you still have no wine to show for it yet.  Time to keep plugging along.  The winemaking process is now ahead!

CRUSH

Red grapes are run through a destemmer to avoid extra tannins in the wine.  Whether a white or red varietal, all grape juice is clear in color to start out.  It’s the time in contact with the grape skins where the wine will pick up it’s color.  These days, some extreme technology is used by some wineries such as optical sorters to only let certain quality grapes into the crush or press.  The grapes are then crushed and then sent into the vessel of choice – usually a barrel for red wines to ferment on their skins.  Red wines will get pressed after primary fermentation.

PRESS

It depends on the winemaker or winery, but white wines can either be crushed individually, or they can be pressed as whole clusters – skins, stems, seeds, and all from which the juice without the skins will go directly into the fermentation vessel – barrel or tank.  White wines won’t stay in contact with the skins during fermentation to avoid picking up too much color and tannin from the skins.  That mixture of skins, stems, and seeds, sometimes called a “pomace” is taken back out to the vineyards and used as fertilizer to aid in next year’s crop.  Nothing is wasted!

FERMENTATION

To recap, your red wines have been destemmed and crushed and are sitting on their skins.  Your white wines have been pressed and are sans skins.  Fermentation is now ready to begin which can last up to a month’s time.  In a nutshell, fermentation is the process of yeast converting the sugar in the grape juice into alcohol.  Once this initial fermentation is complete red wines are usually pressed and only the juice is pumped back into barrels to begin the aging process.

AGING AND MALOLACTIC FERMENTATION

White wines like Chardonnay need to go through a process called Malolactic Fermentation or ML.  ML isn’t actually fermentation at all.  It’s a process where malic acid (tart) turns into lactic acid (creamier – same acid found in milk). This is where the wine develops the creamier, buttery taste Chardonnay is typically known for.  In opposition, crisp white wines like Sauvignon Blanc want to avoid ML, so winemakers will seek to avoid this by filtering out a certain kind of bacteria that causes it.  They’ll also age Sauvignon Blanc or crisp non-malolactic wines in vessels like stainless steel or cement instead of oak barrels.

All red wines will go through ML as well which takes place during the aging process.  ML also gives your wine that silky mouthfeel which is a different way for you to sort out which wines are malolactic when tasting.  Another characteristic is ML wines are typically aged in oak barrels.

As a winemaker, the type of barrel is another stylistic choice that is made. 100% American oak?  100% French oak?  80% new oak, 20% used oak?  Toasted oak?  It’s all up to the winemaker and the final flavor their trying to achieve.

Once ML is complete, sulfur is added to aid in the shelf life of wine and the age ability.  This is usually a very small amount 5 mg/L to 200 mg/L.  A completely undetectable amount.  This process is more important in wines that have higher sugar content to prevent a second fermentation in the bottle.  Essentially, this stabilizes the wine. There are some wines that are sulfite free, but keep in mind you would need to drink the bottle in one sitting after opening it because there isn’t anything to keep it fresh once it has been opened.

Once again, it’s up to the winemaker how long a wine is aged, but Sauvignon Blanc is typically aged for four to six months, Chardonnay will age for approximately 10 to 16 months, Pinot Noir will probably spend about 12 months in the barrel, and Cabernet Sauvignon will age for 16 months to 2 years plus – depending on the winemaker’s style.

RACKING

We’re in the home stretch!  After starting from a barren patch of land to an almost finished bottle of wine – the checkered flag is in sight!

Depending on the winemaker, they will taste their wine throughout the aging process in the barrel, but most certainly all winemakers will taste towards the end of the aging process.  They’ll use a tool called a “wine thief” which is a glass syringe that can extract a small amount of wine at a time from each barrel.

Before the wine makes it to the bottle, the wine is filtered and/or racked to clarify the final product.  What is racking?  Essentially, it’s the transfer of wine from one vessel to another.  The goal in this process is to separate the Lees from the wine.  Lees are the solids and dead yeast cells that settled to the bottom of the vessel during the aging process.  The liquid is typically gently pumped out of the barrel into another barrel.  The Lees is left at the bottom of the initial barrel which is rinsed out with water.  Then the wine sans any solids, is pumped back into it’s initial barrel.

This is done because sometimes the solids can cause cloudiness or unintended flavors in the wine if aged on them for long periods of time.  However, sometimes those solids can add beneficial flavors.  So, this is another one of those things that will be different with every winemaker.  Some may rack their wine multiple times during the aging process, some only once, and some not at all.

BOTTLING

Finally, we’re firing up the bottling line on your first vintage as a vineyard owner!  Depending on how many cases you’re bottling you could be finished in a couple of hours, or a couple of days.  The technology today is designed to bottle quickly at about 85 – 100 bottles per minute.  The bottling line will sanitize, fill, cork, foil, and label the bottles.  There are even mobile bottling lines inside 18-wheeler trucks which smaller wineries use that don’t own their own bottling lines. The larger the operation, the faster the machines!

THE FINISHED PRODUCT!

Congratulations, you’ve done it!  Your first vintage is finally in the bottle.  Wine is a living thing.  So, although it may be bottled and “finished” it will continue to age, mature, change, and evolve into something different in the bottle over time.  Proper storage of your wine is important to be able to enjoy those changes at a later date. A wine fridge is a great idea to keep your wine at a consistent temperature and humidity.  You’ve just spent about five years making the finished product, so protect it’s integrity now and for years to come!