Aaron Berdofe's Wine and Food Experience

Fall at a Minnesota vineyard

Wine and climate are intricately linked. For anyone who has gone through any sort of wine training, you inevitably also get a lesson on macro, mezzo, and micro climates as well. Wine education doesn’t usually touch on genetics (although I feel it should), but climate is one of three factors that influence how a grape varietal expresses itself. The other two factors are soil, and how other living creatures (mainly humans) interact with it. These three factors combined are neatly summed up into the French word, Terroir. One of the fun things in wine is finding that grapes of the same genotype (what it’s born with) will produce wines with slightly different characteristics based on the terroir they exist in. One could also describe this as being a grape’s phenotype.

For a few thousand years the climate where wine grapes were developed and the soils they were developed in have remained relatively the same. The human factor though is what we consider to be the “Art” or “Science”, depending on your perspective of winemaking. The winemaking is a controllable factor. The soil, while not controllable, is a steady constant that only changes when you move the vines. The weather though (a sub-factor of climate), is the unpredictable element. This is why people lament certain vintages and praise others even though today’s winemakers have mostly figured out how to handle the ups and downs of a year’s weather variations. While the weather varies year to year, the winemaker knows the approximate parameters of what it’s going to be like because that’s what climate is.

Now, those climates are a-changing. I suppose you could choose not to believe in that sort of thing, but you’d be hard pressed to find someone in agriculture (Or, you know, Science) that isn’t at least considering how things will change for them in the future. Grape growers and wine makers are no exception. Minnesota Public Radio has recently been running a series on the effects of climate change locally and globally. One of their articles has wonderfully shown how Minnesota’s climate has been changing over the past 100+ years with some pretty specific details so I decided to use that as a jumping point into how Minnesota’s wine industry could see some changes in the future. Give the article a full read here and then come back for my grape-related thoughts below that loosely correspond with their headers.

It’s Warmer and Winters Are Warming Faster

In general, this could be good news for grape growing in Minnesota since our main antagonist is how cold it gets in the winter. Theoretically, if we could eliminate sub-zero temperatures, the number of varietals we could grow would exponentially increase. Currently, zero, that’s right, zero of the European varietals of vitis vinifera that are predominately used for wine making across the world are able to be grown in Minnesota successfully and in quantity to make commercial wine from. This is what has driven the interest and research on hybrid grapes that take the cold hardiness of native grapes (vitis riparia mostly) and the wine making qualities of the aforementioned European grapes. So, hurray if we eliminate those obscenely cold days that stay below zero during the winter.

But it’s not all rainbows and butterflies. What grapes generally don’t appreciate are moody temperature swings. Yes, the idea is to stress the grapes as they grow, but the idea is to do this gradually. Vines (and really all plants in general), keep to a pretty set schedule throughout the year which is dictated by what the weather is doing. When it warms for spring, the buds begin to break and things start to grow. Summer the grapes start appearing and energy production switches to them. Fall, the grapes mature and ripen. Winter, the vine goes dormant to survive the winter. When the vine incorrectly thinks the seasons are changing due to random temperature swings, bad things can happen.

North Warms Faster

There’s really a big divide between the climate of southern Minnesota and northern Minnesota. Currently, although there is certainly debate about this, I would say wines from vineyards from Central Minnesota and south are more favorably received than those of the northern part of the state. One of the major technical hurdles that MN winemakers face is that of having more than the desired amount of acid in the grapes. In general, the colder the region, the more acid will be found in the harvested grapes. There are measures that a winemaker can take to counteract this to a degree, but the more ideal the grape is, the wine will be easier to make as well as potentially better.

It Rains More

This can only be bad. We get plenty of rain in Minnesota. So much, that irrigation of vineyards in the state is rare and if used restricted to preparing vines for winter in the late fall. More water, assuming the vines don’t drown, would mean more vigorous growth of the green parts of the vine (shoots, leaves, etc.). If the vine has to put all of its energy into supporting the green parts, it will put less energy into developing the grapes which means they won’t taste very good. Vine vigor already requires a lot of human power to control, meaning people are out there trimming of excess growth constantly throughout the year. More growth would mean more labor or limiting the expansion of a vineyard…or growing poor grapes.

Intense Storms Are More Frequent

Again, more bad stuff. Intense storms bring about damage to a vineyard. Hail, is an obvious culprit that would rip through grapes, but even intense rains can damage a crop. So short of someone inventing a weather force field, there’s nothing that can be done to counteract this.

Ice Melts Earlier/Snow Season Ends Earlier/Growing Season Grows Longer

You’d think this would be a positive, and in general it is. A longer growing season gives grapes time to spend developing anthocyannins, which turn into the things we associate with flavor in the wine. However, what’s been happening the past few years is that we have a warm spell in early to mid-spring which causes the vines to get started on their bud growth and then the next week the weather plays a cruel joke by snapping the temperature back down below freezing, killing off those buds. While the vines do have a backup second bud (and third), the first is going to be the best. It’s like killing off your kitten and then replacing it with a new one. Not the same, is it? The winter of 2013/2014 was particularly harsh in Minnesota. While the vines themselves survived, most of their buds unfortunately did not. This led to crop losses of up to 90% for the 2014 harvest season.

Hardiness Zones Move North/Species Migrate

I think this factor has the most potential for unknown effects on grape growing. On one hand, moving down hardiness zones into ones that are more common to grape growing is beneficial. However, this also means that the ecosystem that has developed in that hardiness zone is going to migrate north as well. Birds, trees, shrubs, insects: All of these can effect the nutrients in the soil, what pests are going to be found in the vineyard, and how the grapes will express themselves (genetically speaking). The sheer number of factors that go into this is mind-boggling and I don’t believe anyone has been able to come up with a computer model to mimic how this can play out.

In Conclusion…

Outside of climate change, the Minnesota grape growing and winemaking industry really had to conquer one hurdle: How to get grape growing vines that produce tasty wines to survive the winter. This is a really difficult problem to solve, but certainly not unsolvable. In fact, with the recent advances made by the University of Minnesota’s grape breeding project, a lot of progress has been made. With climate change, the hurdles faced by the industry become a moving target. The very problem being worked on today could no longer be a problem in 20 years, but a new one or more likely, multiple problems will have filled its place.