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It was my third trip to the German wine regions, and it was a personal challenge for me to figure out something new I could learn on this particular trip.
As it turned out, I learned quite a lot. I learned that I could order fish and salad at most German restaurants and get a really good meal without a lot of heavy, rich meats and sauces. I learned that I could go for a run through the vineyards in the Rheinhessen and run along the Mosel river, even in February. And I learned that I can tell when a wine has been fermented with naturally occuring wild yeasts, a process also called spontaneous fermentation, and I learned that I actually like these wines.
First, some definitions (from a non-winemaker, essential lay-person):
Spontaneous fermentation, a.k.a.
wild yeast fermentation or
natural fermentation is method of wine production which does not use the addition of yeast to start and control fermentation of the grape juice. Instead, grapes are crushed and allowed to ferment on their own. Grapes have yeasts living naturally on their skins. These yeasts can begin to go to work on the grape juice when the conditions are right, ie. they have a nice warm temperature, plenty of food, that sort of thing. They stop working when the alcohol (which they produce from the sugar in the juice) eventually kills them, or the temperatures get so they can't live or reproduce very well (when it gets too cold).
Cultured yeast fermentation is the usual, conventional way of making wine now, which is where you add some purchased yeast and add it to your grape juice after crushing the grapes. This reminds me of making bread. When you open that package of Fleischmann's yeast and add it to warm water and sugar, and those dried yeast guys suddenly liven up and start eating the sugar in the water and make bubbles.
In the Rudi Wiest portfolio, there are several producers that are known for using wild yeast fermentation on their Rieslings, as opposed to cultured yeast fermentation. They are:
Joh. Jos. Prum in the Mosel,
Schloss Lieser also in the Mosel, and
Schafer-Frohlich in the Nahe.
In the past, before this most recent trip, I admit that I actually did not like Rieslings made with wild yeast - I found their aromas to be muted, slightly beer-y and sometime sulfury, instead of what I expect Rieslings to smell like - fruity, floral, and everything nice and clean and bright.
However, this time, in tasting the 2009s - and this may have been because the 2009s were so expressive - I found that I really enjoyed the Rieslings fermented with wild yeasts.
The reason for using wild yeast fermentation is to show the terroir of the vineyard in the wines not only by using all that is in the grape - the juice, the skins, the seeds, but also using the organisms living on the grapes - the yeasts - to do the work of making the wine, instead of adding cultured yeasts to do the job. The idea is that the wild yeasts are different in each location, and they taste different, whereas cultured yeast give you good, clean, predictable results, leading to the assimilation of wine - ie. your wine ends up tasting like your neighbor's wine and everyone else's that uses that yeast. With natural yeast, you get more variation between wines.
And with it, you get more yeasty aromas - aromas of beer, bread, sometimes reminiscent of sulfur too. But this year, when I smelled and tasted the wines made through spontaneous fermentation, I found depth, intrigue, delight. Instead of polished clean, fruity clear Rieslings, I found Rieslings with soul and depth, interest, and character. Like a person who has not a perfectly symmetrical face and a 36-24-36 body and perfectly straight teeth and flawless skin, but a person you don't think is beautiful initially until you get to know her, then you see how different she is from the others. You get a sense of where she comes from, what she's done, what she's been through, and how she got there - the hard way, the patient way, the right way, on her own, without guarantees of success, with more danger and risk. That's a Riesling fermented spontaneously.
The wines from Joh. Jos. Prum, Schloss Lieser, and Schafer-Frohlich were among my favorites this year, and that is a first. I admit to not having given enough credit to these wines because they aren't obvious supermodels evident to everyone at first - they take time to appreciate. I've been working around these wines for 3 or 4 years and it is only now that I would reach for one of these instead of their simpler, cleaner cousins.
Who knows what will happen next year? Perhaps next year I'll prefer the more minerally ones..... wonders never cease when learning about wine.