Shellfish and chitosan
We’ve all heard of comments about sulfites or phenolic compounds causing headaches, but I use chitosan and kielsosol for clarifying agents. Chitosan is made from shellfish byproducts — could these cause an allergic reaction (headaches?) to those who are allergic to shrimp or lobster?
Though I’m no medical doctor (I seem to say that a lot in this column), from what research I was able to pull together, if I personally had a shellfish allergy I would feel comfortable using chitosan products to clarify my wine. I will let you make up your own mind (in conference with your physician of course), but from what I understand, seafood allergies derive from proteins in crustaceans and shellfish, not from materials in their shells.
Chitosan is a manufactured product that is derived from chitin in the shells, a natural polymer. During the manufacturing process, the shells only (no fleshy protein bits) are used, and any protein that could possibly be clinging is removed.
Chitosan is a great flocculating agent in wines. It precipitates solids and is a very efficient clearing agent — basically you add it to your wine, it gloms on to solids and then falls out of solution to the bottom of your container. If you rack cleanly enough (which means giving the solids plenty of time to settle) you should be able to leave the chitosan fining agent, plus the tannins and wine proteins it pulled out, behind in your container.
Grape varieties for dry climates
I live in an area that gets about 10” of rain a year. I have read that Grenache and Mourvèdre do well in hot and dry climates but what about hybrids? Are any of the direct hybrids suitable for hot and dry climates? Would Norton do well in such a situation? Baco Noir?
Not to disparage hybrids, but since you’re in sunny Southern Arizona, why not try your hand at traditional European Vitis vinifera? You live near Sonoita, the only AVA (American Viticultural Area) located within the state of Arizona, and your viticulturally-inclined neighbors are already having success with wines from Cabernet Franc to Viognier. Most hybrids (usually Vitis vinifera crossed with a native American variety) are designed to resist rot, mildew, and frost- conditions, which you don’t have to worry about in your climate.
Though I know this will probably spark a lot of controversy among the Wine Wiz readership, there’s no getting around the fact that hybrids are just that — and just won’t make wine identical to the traditional varietals you might have as favorites, such as Cabernet Sauvignon and Chardonnay. There’s no doubt that in favorable climates like Arizona’s, and in the hands of a conscientious winemaker, hybrids can make some good wines. Baco Noir seems to be a favorite with hybrid growers right now.
However, I would talk to your local cooperative extension, Master Gardener’s Group or even the Arizona Wine Grower’s Association (see contact information on the next page) for advice as to what they believe will be the best varieties to try in your region. Because they are specifically bred for colder, wetter climates, it’s likely that some hybrids won’t do as well in your very Mediterranean climate as they might, say, in Michigan or Missouri. Whites, especially, are prone to sunburn while hot winds can make thin-skinned hybrids shrivel and turn into raisins. In addition, there are also Vitis vinifera varieties that will do better in southern Arizona’s hot, dry climate. Knowing what I do about California viticulture, I would be tempted to try reds like Syrah (AKA Shiraz), Grenache, Carignane, Zinfandel, Nebbiolo, and Petite Sirah. These are all reds that like the heat and are best when made in a ripe, rich style, which you will get with your ample sunshine. If you aren’t a red wine kind of guy, I would stay away from Chardonnay and move more towards the Rhône whites like Viognier or to the Muscat family, like Orange Muscat, Malvasia Bianco and Muscat Canelli. I have made wines from these grape varieties out of warm areas like California’s Lodi region and Southern Monterey county with quite a bit of success.
Don’t forget that grapevines, even though they’re one of the most drought-friendly crops, still do need a good amount of water. Estimate 250–350 gallons (946–1,325 L) per vine per year from bud break to harvest, even more during heat spikes or if you’re trying to establish a young vineyard. Again, your university extension or local gardening organizations can help you fine-tune a plan for your particular microclimate. Why not order a copy of the Arizona Viticulture Guide? $30 (see address, next page) seems like a good first investment if you’re serious about planting a vineyard.
To order your Arizona Viticulture Guide, please send a $30.00 check or money order made out to Dr. Mike Kilby.
Dr. Mike Kilby
PO Box 1567
Sahuarita, Arizona 85629
Arizona Cooperative Extension
840 Rodeo Dr. # C
Prescott, AZ 86305
Arizona Wine Grower’s Association: http://www.arizonawine.org/
UC-Davis graduate and professional winemaker Alison Crowe has been answering hundreds of your winemaking questions as the “Wine Wizard” since 1998. Her Wizard columns have been collected in “The Winemaker’s Answer Book” which is available at winemakermagstore.com.