Climate is at the core of quality winemaking, but the concept isn’t quite that simple. There are many factors that determine the climate of a given wine region: latitude, elevation, aspect, sunlight, soil, geographical features, and more. It’s interesting, though, since grapevines themselves must take root on land, that one core geographical feature that lends itself to excellent winemaking isn’t actually on land at all: it’s water! Several of the world’s most prominent winemaking regions, both established and up-and-coming, are positioned near major lakes. So the question is: Why exactly do lakes produce such great wine?

All bodies of water have significant effects on the climate of their surrounding wine regions, but unlike oceans, which have temperatures affected by major water currents, and rivers, which are in motion and can vary in size, large lakes can act as make it or break it factors for winemaking. Essentially, the lake acts as a moderating influence for surrounding temperatures, due to the fact that water changes temperature at a much slower rate than air, maintaining its temperature (whether warm or cool) for a longer period of time. Think of it this way: When turning on a gas stove, the air surrounding the flame becomes hot instantly, but it would still take a pot of water several minutes to boil.

The effect of this moderating influence varies, depending on the other climatic factors of the region. For some very cold wine regions, grape growing simply would not be possible without the presence of a lake. Because lakes can retain heat, they warm the surrounding land, preventing roots from freezing during cold winters and protecting vines against sudden spring frosts and freezes. This lake effect is also helpful at the end of the growing season, allowing temperatures to remain warm enough for grapes to sit on the vine into autumn. Otherwise, grapes might not have time to fully ripen in these cool areas.

Warmer winegrowing regions can also benefit from extended growing seasons, allowing winemakers to make richer, riper styles of wine, or even allowing certain grapes to gain enough sugar to make lusciously sweet wines. And just as a lake retains heat in the winter to warm surrounding vineyards, it maintains a cooler temperature than the air in the summertime. Cool breezes from the shore can be hugely beneficial to maintaining acidity in grapes during this season, particularly in continental climates where many of these lakes are located, as temperatures can soar extremely high.

For a taste of the lake effect, seek out a bottle from one of these four lake wine regions, all with different styles and climates.

Franciacorta

The northern Italian region of Lombardia has many glacial lakes; some, like Lake Como, are more famous than others. The region’s most famous winegrowing area benefits greatly from lake influence. Often referred to as the “Champagne of Italy” due to its traditional-method sparkling wines, Franciacorta is located just south of Lake Iseo in central Lombardia, where the foothills of the Alps turn into well-drained rock and limestone hills left behind by ancient glaciers.

Though the region as a whole is cool, Franciacorta itself would be warm enough for grape growing even without the lake’s influence, but its presence gives the region a mild climate and riper grapes. Sparkling wines are made from Pinot Noir and Chardonnay, as in Champagne, and can also include some Pinot Blanc, but the wines as a whole tend to be richer, with more body and fruit.

Neusiedlersee & Neusiedlersee-Hügelland

Landlocked Austria may typically be defined by its most prominent geographical feature, the Alps, but in the region of Burgenland, one lake completely changes the kind of wine made in the surrounding vineyards: the Neusiedlersee (a.k.a. Lake Neusiedl). A large, shallow lake near the Hungarian border, the Neusiedlersee acts as a moderating point between Alpine drafts from the northwest and warming breezes flowing across the Hungarian plains. The surrounding regions, Neusiedlersee (yes, it’s the name of both the lake itself and the region, just to keep things confusing!) and Neusiedlersee-Hügelland, therefore benefit from a long, mild growing season, hence why these areas are able to ripen some of the red grapes, like Zweigelt and Blaufrankisch, that other Austrian regions cannot.

The lake also has one more important effect on the surrounding vineyards: moisture. Autumn mists rise from the lake into the vines, and this warm, damp environment encourages the growth of the noble rot botrytis. Thus, a specialty of both Neusiedlersee and Neusiedlersee-Hügelland is botrytised sweet wine, with even rare Beerenauslese and uber-rare Trockenbeerenauslese styles able to be produced fairly consistently vintage after vintage. The town of Rust on the western bank of the Neusiedlersee is even home to a traditional style of botrytised sweet wine called Ausbruch, which bears many similarities to Hungary’s Tokaji.

Finger Lakes

Given the name of the region, it’s unsurprising that lakes have an influence on the climate of the Finger Lakes. This upstate New York region tends to be cooler, but the lakes moderate the climate of the surrounding vineyards, allowing winemakers to experiment with a variety of both Vitis vinifera and hybrid grapes, though cool-climate varieties such as Riesling have garnered the most acclaim. The lakes also elongate the growing season, helping grapes to fully ripen and allowing some winemakers to leave healthy grapes on the vine until the winter months for the production of ice wine, a dessert wine made from frozen grapes.

Not all of the Finger Lakes are created equal when it comes to grape growing, however; Cayuga Lake and Seneca Lake are the deepest and lowest in elevation of the 11 and therefore have the biggest impact on their surrounding vineyards. It is unsurprising, then, that these two lakes have the highest concentration of wineries. In general, vineyards situated toward the northern portion of the lakes are located closer to the shore, to benefit from as much of the moderating effect as possible, whereas more southern vineyards can be positioned a bit farther away.

Michigan

Yes, the state of Michigan makes quality wine, and it simply would not be possible without the presence of a lake. In fact, nearly all of Michigan’s grapevines are located within 25 miles of Lake Michigan’s shores. The state’s four key regions – Leelanau Peninsula and Old Mission Peninsula in the northwest, near Traverse City, and Lake Michigan Shore and Fennville in the southwest – would simply be too cold otherwise, particularly to grow Vitis vinifera varieties.

Even with the lake’s warming influence, cool-climate grapes tend to thrive in this cooler area –Riesling, Chardonnay, Pinot Grigio, Pinot Noir, Cabernet Franc, and Syrah, among others. Michigan’s location still makes grape growing tricky, however; in early 2014, the infamous polar vortex froze parts of Lake Michigan, destroying much of its beneficial lake effect and killing many dormant grapevines, particularly red varieties.