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WINEMAKING If you want a non-buttery but malolactic Chardonnay, co-ferment and hit it with sulfur as soon as the malo completes; if you want a butter bomb, stretch the malolactic fermentation out as long as possible. siderations that may weigh for or against a particular protocol, and winemakers have to calculate the odds, batch by batch. Most sup- pliers have or can tick off a checklist or score- card of relevant considerations for deciding how to proceed. Here are the most significant ones, culled from a range of vendors. Know your grape sources. Have grapes from a particular vineyard been prone to sticking in the past? Or has handling the fruit been a breeze? For that matter, for a new vineyard source, do you really know anything about what you are deal- ing with? Know your grape chemistry. If the potential alcohol from your fruit's Brix is above 14%, you may want to think twice. If the fruit comes in with major YAN and nutrient deficiencies, co- fermentation might stress it even more. If the pH is less than 3.2, promoting malo under any circumstances is going to be difficult. If the pH is above 3.6, the bacteria may decide to feast on sugar, not malic acid, producing more VA and the likelihood that both fermentations will have to compete with a gallery of spoilage critters. Measure the malic. Malolactic fermentations work best, not sur- prisingly, when there is a good supply of malic acid to chew on. If the malic is less than half a gram per liter, the bugs may suck impact; a simultaneous malo (or, for that matter, any malo) will have trouble getting going with more than 40 ppm of total SO2 . Initial SO2 additions at the crusher can have an or Know your yeast strain. Yeast strains differ wildly in their nutritional demands; some are real hogs, which can deprive a simultaneous malolactic fermentation of what it needs, or conversely, the malolactic can cut the legs off a particularly demanding yeast. The Champagne yeasts—EC1118, PDM, etc.—are notorious in this regard, which may be one reason for so many co-fermentation train wrecks in in the bad old days. Yeast strains also vary in their propensity to produce sulfur dioxide and fatty acids, both of which can be bacterial inhibi- tors. But as Russ Robbins notes, "The majority of modern yeast strains have been tested for their compatibility with malolactic bacteria, so we know they work." Information about which strains are friendly and unfriendly for co-ferments is readily available and might be more important than whether a particu- lar strain promotes red or black cherries. Timing the timing. The umbrella term co-fermentation covers a variety of timing strategies, all with their advocates: co-inocula- tion, early inoculation, late inoculation and sequential inocula- tion. Though the term "co-inoculation" is often tossed around as a synonym for co-fermentation, it more properly refers to adding both inoculants at exactly the same time, up front. This is not the most common recommendation, though Lars Petersen of Gusmer thinks it gives the bacteria lead time to build up a population, in- surance against the occasional risk that a stressed yeast will spike in SO2 15 ppm free SO2 production and kill off a smaller, newly introduced bacte- rial population. For the most part, suppliers suggest "early inoculation"—wait- ing 24-48 hours, or until there are clear indications that the yeast fermentation is up and running. Van de Water offers cap forma- tion as a rule of thumb. This way, you know the yeast is func- tional, and a good bit of the SO2 will already be bound. My hunch (and Petersen's) is that this slight bit of caution comes partly from wanting to make sure the primary is off and running, and partly from wanting to offer winemakers a comfort level and let them sleep better at night. "Late inoculation" means adding bacteria near the end of the alcoholic fermentation—down at 2° Brix or lower, which positions the bacteria to rev up as soon as the pri- mary slows down. Duncan Hamm, who works with Chr. Hansen products on mul- tiple continents, offers the generalization that the Europeans do a lot of early inoculations (at least for top-tier wines); the Austra- lians do a lot more conservative late inoculations (often coincid- ing with early pressing at low Brix), and the U.S. remains the most wed to sequential timing. Listen to your wine. This gratuitous piece of advice applies to a lot more than malo timing, though it applies there as well. In a co-fermentation, keep an eye out for trouble such as temperature swings, excessively rapid fermentation or upsettingly slow fermen- tation. The primary fermentation deserves all the attention you can spare; the malo can be fixed later. Managing co-fermentation requires a certain level of technical knowledge but also involves just paying attention. Think about wine style. Besides affecting microbial performance, co-fermentation can have an impact on the style of the finished wine. Some studies have indicated that successful co-fermenta- 54 WINES & VINES OCTOBER 2012 . it up in short order and move on to eating citric acid or sugar, which might not be a good plan. If the malic is extremely high, co-fermentation may prove difficult as well. Easy on the SO2