Mother Nature and Mr. Freeze Do a Number on the Grapes

Wineries are an extension of farming, and therefore are subject to the whims of Mother Nature. For the Willamette Valley and southern Oregon, harvest 2007 will be remembered for the rainstorms that rolled through, slowing end of season ripening and diluting the grapes. In 2008 we faced the cold – parts of the Rogue and Applegate Valleys were hit with hard freezes (temps in the 20s) this past weekend, mid-harvest for many. It was only supposed to hit the mid 30s. That Mother Nature, she’s a sneaky gal.

What do freezing temperatures do to wine grapes? It is not as bleak as it sounds. The biggest impact is that it kills the vines’ canopy (the leaves) – so no pretty fall colors, just dead, black leaves. This halts photosynthesis immediately, meaning the vines no longer convert the sun, water and ground nutrients to sugar – the grapes are essentially frozen in their development. No more ripening. This is especially difficult when dealing with later ripening grape varietals like Tempranillo and Cabernet Franc, which in 2008 had probably 2 or 3 more weeks to go before being ready for harvest. Planting those varietals in areas susceptible to early frosts is risky – but when the weather cooperates, the results are worth it – complex wines that benefitted from cooler temperatures with minimal heat spikes. Risk tastes good.

Southern Oregon is loaded with micro-climates: different vineyard sites were hit with frost in varying degrees. Lakeside Vineyard in Talent looks like a set for a Halloween movie, with creepy black vines sagging and crackling. Luckily for us, the Syrah had hit sugar and acid number within our range prior to the freeze. In fact, the numbers are almost identical to 2005, and that vintage turned out okay (Best of Show at the National Women’s Wine Competition, “Outstanding” from Wine Press Northwest, and an astounding 97 points from AlaWine, etc, etc, etc). We let the grapes hang on the vines for five days following the freeze to allow a bit of dehydration to occur – this concentrates the fruit flavors.

Fortmiller Vineyard is also in Talent, but it is about 500 feet higher than Lakeside, which usually protects it from frost. The vineyard is bowl shaped, with a lake in the middle. We all know that heat rises – and conversely, cold falls. The chilly air settled over the lake, and only the handful of vines ringing the lake were damaged. Warmer air moved back in and ripening should continue for the next ten days to two weeks. The vineyard’s bowl shape also helps retain heat, so even after the sun has passed by, the residual warmth remains.

And in a mere two years – or more – we’ll have the results from harvest 2008. I can hardly wait!