How the 3 processes of making late-harvest wines impact their flavor styles.

Isabelle Lesschaeve Author

Late-harvest wines have intense flavor profiles and a sweet taste. Letting the grapes dry on or off the vines deliver different tasting experiences.

Published 23 February 2023

Attending academic conferences is one of the most exciting parts of academic life.

• You gather with your peers in a nice location,

• you share your research work

• you participate in social events to bond, exchange, and debate.

What a lovely summer break.

Now, imagine a bunch of academics attending a wine marketing conference in Bordeaux, France.

The local Business School hosted us in their facilities. They organized the most gargantuan dinner events and scenic winery tours I had yet to experience.

I chose to visit Sauternes because I have a sweet tooth and love pairing a Sauternes wine with foie gras during the holidays.

So I embarked on a tourist coach with my colleagues and visited several wineries in Sauternes.

A memorable experience with late-harvest wines

My most memorable experience was at the Chateau de Myrat, where the owner, the earl de Pontac, hosted us. It was a very down-to-earth experience, not what one could expect from the French aristocracy. And I loved it.

Like many family estates, the earl shared the challenges of maintaining the buildings and grounds to their original glory. He was full of charm and had a lot of humor. We all had to pause with this huge bottle of his production.

The earl took us to the vineyards and the cellar. 

He was very knowledgeable of the science of making botrytized wines, a late harvest wine style caused by the berry infection by botrytis cinerea.

As the grape clusters dry on the vine, they get infected by a fungus called botrytis cinerea. It looks ugly: it's gray, a bit hairy, although we call it "noble rot" in French, "la pourriture noble." 

The process of making delicious Sauternes wine combines the dehydration of the berries and some biochemical reactions due to the plant reacting to the fungal infection. The result leads to flavor and sensations that differ from wines made without fungal intervention.

Sauternes is only one style produced by a late harvest.

Late-harvest wines can be obtained by two different methods. 

Whether the vintners let dry the grapes on the vines or pick them up at an expected harvest date and take them to a different facility to dry them.

What happens to the grapes with a late harvest?

The grape berries ripen for a longer time and dehydrate slowly so that they concentrate on sugar and flavors. And that's really what late harvest is really about. Whether the dehydration happens on the vine or off the vine.

And to be successful, the drying process on the vine has to happen in a very dry and very aerated area. So sun and wind are the conditions needed for a successful drying process on the vine. Otherwise, as we know, the rot would come in, and then the crop would be gone.

So late-harvest wines are made in dry regions in the fall, and the wind is very important.

Is icewine considered a late-harvest wine?

It is to me, at least.

The vintners can let the grapes dehydrate and freeze naturally in Canada and other cold climate regions. So the harvest isn't delayed by a few weeks but by several months.

Donald Ziraldo, the co-founder of Inniskillin Wines with Karl Kaiser, describes icewine making as extreme winemaking in his book of the same title.

Here are a few interesting facts about icewine:

• The Niagara wine area in Canada is the only region that can produce every year icewine.

• The harvest and winery operations are closely watched by the Vintners Quality Alliance, the province regulation body.

• The environmental temperature has to be at all times -8C (17.6 F) or less to qualify the wine production as icewine.

• That's why the harvest happens most often in the middle of the night.

• Pressing frozen grapes is a game of patience, and fermenting very sweet grape juice is a challenge that can lead to stuck fermentation, the yeasts stopping the conversion of sugar to alcohol.

• Researchers at CCOVI found that the number of freeze/thaw episodes before the harvest was instrumental in delivering the unique flavors.

Extreme winemaking, indeed!

Drying grapes off the vine.

Traditionally, people will spread the grapes on the ground under the sun, and that's also a way that people would do raisins.

Another process is to lay the grape clusters on straw and clay in a very aerated environment so that they can dry. And here also, it's very important to control the humidity so that the clusters aren't affected by mold. So that's why it's very aerated, probably in a windy environment, to let the grapes naturally dry.

What flavors can you expect when tasting late-harvest wines?

Watch the video or continue reading.

 We can definitely expect a concentration of varietal aromas and of sweetness.

The sweeter juice will develop some viscosity; the mouthfeel will be a bit thicker.

The aromas will be more concentrated, not specifically cooked, but more concentrated and more intense.

It's important for the wine to still exhibit some acidity to avoid a cloying mouthfeel. 

I guess it's a question of how the wine is made and of balance between the acid and sweet taste. Indeed, when you drink something very sweet, it can be very heavy and sticky in your mouth, but the acidity balances that effect. So it can be more pleasant to drink, easier to swallow, and to appreciate.

The botrytized wine flavors result from the berries' biochemical reactions due to the fungal infection. 

You will still perceive the varietal aromas, but they tend to be muted and transformed. So we will still have some citrus fruits in the white wines, maybe some tree fruit like peaches and apricots. But then, you can have other flavors like caramel, toffee, mushrooms, or even nutty flavors and honey.

When I ask my subscribers: what aromas would you expect to smell or taste in a botrytized wine? 

>> these terms came up often: honey, beeswax, and orange marmalade.

Late-harvest wine-tasting notes

I hosted a tutored tasting on January 21, 2023. We tasted 3 wines:

1. A German Riesling from the Mosel, late harvest (Spatelase) and dry (Trocken) - 2019 Selbach Oster

2. A California blend of Semillon-Sauvignon blanc, late harvest naturally infected with Botrytis cinerea and with a sweeter style - Dolce 2015

3. A straw wine - Mullineux 2017

Here are my tasting notes:

Have you tasted these wines?

Let me know your thoughts.

Categories: wine aroma, wine style