Phillippe Renaud, left, and Daniel Attinger make a tiny toast with wine from Attinger’s microfluidics fermenter, front and center. How does it taste? Meh, Renaud says. (Photo credit: Ecole Polytechnique Fédérale de Lausanne)
For centuries, winemaking has been a messy, time-consuming operation, taking weeks just to ferment and sometimes years to mellow grape juice into something you’d actually drink.
Now an Iowa State University professor is raising the hopes of oenophiles around the world by short-circuiting the process, producing wine in just minutes.
There are, of course, a few catches. And just as importantly, the technology, revealed earlier this summer, is more a feat of engineering than oenology.
Daniel Attinger, an ISU associate professor of mechanical engineering, grew up in the Canton of Valais, a prominent wine-making region of Switzerland. Naturally, he’s a wine connoisseur himself, but his research focuses on multiphase (involving multiple versions of matter, like liquid and gas) microfluidics. Microfluidic devices are the integrated circuits of the liquid world: Instead of microscopic wires transmitting electrons to transistors, they use tiny channels to move minuscule amounts of liquids and gases, dispensing or performing chemical reactions on them. Microfluidics have wide applications in chemistry, biology and other fields, with devices like a “lab on a chip” capable of instantly analyzing small samples of blood or other fluids, the gene chip and inkjet printers.
Or as tiny wine factories. Working with colleagues at ISU and at his alma mater, Switzerland’s Ecole Polytechnique Fédérale de Lausanne (EPFL), Attinger has developeda tiny, microfluidic winery.
Adding yeast to grape juice, of course, makes wine. The microscopic organisms consume sugars in the juice, converting them to alcohol and carbon dioxide. Fermenting whole barrels of wine can take weeks.
Attinger’s microfluidic device does the same thing in minutes. As described in an EPFL account, the grape juice flows through a micro-channel. Yeast is held in adjacent compartments, separated from the channel by a thin membrane perforated with nano-scale holes just billionths of a meter in size. When the juice reaches the yeasts, they absorb the sugars and pass alcohol and carbon dioxide through the pores.
Because the juice and the yeasts are restricted to such a small space, fermentation is fast. The other advantage, Attinger says, is that the two are kept separate. In full-scale wineries, it can take weeks to separate wine from yeast.
Sounds great, huh? One wine-besotted writer has even (jokingly) demanded that Attinger and his colleagues sell her a microwinery – now.
But if you’re dreaming of instant wine, you’re (not so) high and dry. While Attinger’s machine can ferment grape juice non-stop, it produces only about one milliliter – less than a quarter teaspoon – per hour. Getting even a goblet-full would take all day; several days for a bottle. Plus, as Phillippe Renaud, head of EPFL’s Microsystems Laboratory, says, the microfluidics device “uses a simplified process and the result is currently not as good as normal wine.”
So what’s the point? The art of winemaking lies in adjusting the process to account for the grapes’ quality, which varies due to growing conditions each year. Vintners choose from hundreds of yeasts to produce different tastes and alcohol contents. They can adjust the fermentation temperature and other factors.
Attinger’s device would reduce some of that guesswork. Perhaps a winemaker finds that one type of yeast or a particular fermentation temperature makes overly bitter wine, Attinger says in the EPFL story. The microfluidics device would let them quickly test different combinations of yeasts and temperatures under controlled conditions to produce the best results.
That ability to adjust is especially important, Attinger says, because climate change is having a drastic effect on grape production. Crops may mature at a faster pace than usual, leading to unpredictable alcohol contents and flavors. Winemakers must adapt.
The microfluidics device also could have uses beyond winemaking, too, since fermentation is used to produce useful substances in many fields, from pharmaceuticals to biofuels.
Source: Iowa Science Interface