|Cacao Prieto's hybrid copper pot still|
The weekend has passed, but what a fun weekend! After a fantastic evening at the Manhattan Cocktail Classic opening gala on Friday, I headed on over to my first MCC event on Saturday afternoon, the Hands-On Distilling Workshop: The Art and Science of Distilling. The seminar was held at Cacao Prieto in the Red Hook part of Brooklyn. Cacao Prieto is a young business started by former aerospace engineer Daniel Prieto. The presentation was done primarily by Preston and Dr. Randal Murphy, PHD, a Chemist with the company (and apparently a college professor of Preston's). As they described, Cacao Prieto is effectively a tripartite business: a chocolate producer using cacao imported from the Dominican Republic; a distillery (primarily of rum, although they are branching out into other products, including a cacao liqueur and a whiskey); and a biotechnology arm looking at potential medicinal and other useful properties of cacao. Among other interesting facts, Cacao Prieto touts having received the first license to distill rum in New York City since prohibition.
In the course of a the near-three hour session, the presenters took us through a rather detailed look at the technology and science of distillation. The presentation covered some history of distilling and other methods of alcohol extraction, different types and variations of stills, and the specific chemistry of the distillation process (slides of molecular models and all). The presentation was quite interesting, even if some of the specific science may have gone over my head at times (my last serious science class was more years ago than I care to think about). Here are a few tidbits that I found most memorable/most interesting:
- Among the alternate ways to extract alcohol from fermented liquid is freezing. Freezing causes water molecules to solidify while leaving a higher alcohol solution in a liquid state that can then be poured off (the process can be repeated until a maximum threshold is hit, which I believe was around 25%).
- At the top of a pot still or hybrid pot still (the latter being the type used at Cacao Prieto), there is always a type neck where the end product moves on to the next stage. The shape of this neck actually has an impact on what components move on (and thus of course the flavor). Different kinds of necks are actually used for different types of spirits (and among different national producers, e.g. Irish whiskies versus Scotch or American, etc.).
- There are several different types of column stills. The presenters discussed in particular the packed column design and the bubble plate design (the kind used by Cacao Prieto). In distillation setups involving different levels of plates, different levels of heat are applied at the various stages of the column, with the hottest temperature applied at the bottom. There are plates at the different levels that effectively facilitate a kind of mini-distillation at each level as different cogeners evaporate based on different boiling points. It's these different plates that make marketing about "three times distilled" vodka and the like relatively meaningless, since it can simply refer to additional plates present in the still setup rather than actual re-distillation of the product.
- In the bubble plate design, there is a liquid at each stage which effectively catch certain components of the vapors and filter them out. If the liquid bubbles over a certain height, it is caught in a return that returns it back to the bottom of the column where it can rise through again.
- Distillation by itself cannot produce pure alcohol. To go beyond a certain point (somewhere around 196 proof), additional processing has to be applied, which commonly either means adding something to the distillate that will in essence act to soak up some of the water molecules or by using vacuum filtration to bring up the level to a higher proof (both of these are comparatively expensive processes to apply, so they are generally done at large producers, not micro-distilleries).
- Some larger distilleries actually produce industrial ethanol and their beverage products from a base of the same distilled pure, or near-pure alcohol. In essence, to make the pure alcohol taste, for example, like rum again, they add back in flavor components until it reaches the desired flavor profile.
- The effect of barrel aging is three fold: it causes some matter to be added to spirits, some matter to be removed, and some reactions to be catelized between what is in the distillate and what is the wood.
- Charring barrels has the effect of catelizing some reactions between the distillate and the barrel, and also acting as a barrier between the distillate and the outer wood. The thickness of the char can have an impact on the end product, as can the rate and temperature of the charring.
- The idea of just storing distilled or fermented product in an oak barrel for some number of years and hoping for the best is largely a fiction. First, aging using oak doesn't necessarily mean a barrel on the shelf. Aging is sometimes done by adding oak staves to glass containers (which are less prone to evaportation than barrels) or adding oak or other wood chips. Further, there is constant monitoring of the product as it ages, often with various additions and adjustments being made (for example, in the case of aging wine, even the most traditional of producers will still add tanins to the barrel during the aging process to adjust the flavor). Even the design of warehouses for storgage of barrels incorporates knowledge of how the sunlight might hit the buidling and the heat and airflow within each floor of the building.
- New Yorkers might appreciate knowing that in the initial attempts at distilling rum at the Brooklyn location, the staff at Cacao Prieto tried using NY tap water. The result was the yeast died. In short, they learned that using NY tap water would entail using filtration and lots of nutrients to keep the yeast clinging weakly to life. Today, they instead use spring water from upstate New York from an area once involved with limestone mining, which apparently the yeast was very happy with (limestone content is said to be one of the things in the water in Kentucky that also helped the Bourbon industry explode there).
During the course of the presentation, the staff also began an actual distillation of some rum in the next room. As the presentation went along, they passed around a sample of the distilled product at various stages so we could smell and, in the latter cases when it was more of a consumable product, taste the differences after different time periods in the process. We also got to have a brief tour of the facilities, including a look at a small rotovap still occassionally used for special products, and their fermentors.
This was the only Saturday even I attended at the MCC, however coincidentally, my friend and I (after a few stops including drinks at Amor y Amargo and dinner at Prune) met up with a colleague of hers and some friends that had also been hitting some MCC events, including one Traveling Foodie. The result was a late night of dancing at a Soul Night somewhere in Brooklyn if my admittedly impaired memory serves. I definitely can't complain about ending the night with an evening of dancing with four lovely ladies. More stories of the weekend to come soon...