Coffee Nerd

the little coffeeCoffeeTalk is proud to provide a series of sneak previews of Dr. Shawn Steiman’s new book, The Little Coffee Know-It-All: A miscellany to growing, roasting and brewing the world’s best coffee, uncompromising and unapologetic.

Dr. Steiman’s forthcoming book explores the multiple aspects of the coffee plant and of coffee production through the lens of a scientist. And while backed with scientific data and facts, his easygoing and informal writing style makes it accessible knowledge to all.

Shawn is a coffee scientist, Q-grader, author, and consultant. He’s a graduate of Oberlin College as well as the University of Hawai‘i. His coffee research has included coffee production, entomology, ecology, physiology, biochemistry, organoleptic quality, and brewing. Aside from being an owner of Daylight Mind Coffee Company, he also owns Coffea Consulting, a coffee-centric consulting firm. Shawn regularly presents seminars, workshops, and tastings for both public and private events.

Why can’t I call it a siphon brewer?

There are a variety of methods for brewing coffee, each manipulating the brewing parameters slightly to produce a different end result. To describe them all individually would be not only be overkill, but tedious and boring to read. There is one method, however, that warrants a closer look. Not only does it draw upon some of the chemistry/physics principles discussed earlier, but it is a fascinating and mesmerizing brew method that intrigues everyone who sees it. This brewer, the vacuum pot or siphon brewer, also happens to be a darling of the specialty coffee industry right now.

This beautiful and interesting brew method has been around since before 1827. Often when someone first sees a vacuum pot brewer, they think of laboratory chemistry. The common vertically aligned, two-compartment contraption that begins with water on the bottom and coffee on the top certainly presents an image of scientific mystique. Apply some heat and the water moves to the top chamber, through a tube, and mixes with the coffee. Remove the heat and the now-brewed coffee returns to the lower chamber while the coffee grounds remain on top, thanks to a filter nestled in place at the top of the tube.

All of this sounds very complicated. One might even think the name, siphon pot, alludes to how it works. Unfortunately, no siphoning is occurring using this brew method, making the name rather fallacious. Let’s explore just how this brew method works and discover why they should always be called vacuum pots and not siphon pots.

Implications for the cup profile

This brew method is a fun presentation of some basic scientific principles. It also tends to be well regarded as a method of brewing coffee. While the vacuum itself probably doesn’t impart any influence on the taste of the beverage, the method does offer two unique aspects that likely do influence the taste.

First, while the coffee is in the upper compartment brewing, the heat from the rising steam allows the temperature to be held constantly at the proper brewing temperature. Other brew methods begin with properly heated water but the water quickly cools as it comes into contact with air and the coffee bed. How this influences the taste has yet to be documented.

Second, there is always a small amount of water that remains in the lower compartment. When the coffee returns to the lower compartment, it mixes with this water and becomes diluted, a process unique to this brewing method. This, too, needs exploration but it seems reasonable to guess that it is analogous to adding a few drops of water to a scotch.

Dr. Steiman has authored numerous articles in scientific journals, trade magazines, newsletters, and newspapers. He is the author of The Hawai‘i Coffee Book: A Gourmet’s Guide from Kona to Kaua‘i and is a co-editor and author of Coffee: A Comprehensive Guide to the Bean, the Beverage, and the Industry. His forthcoming book, published © 2015 by Quarry Books, will be available in the spring of 2015. Stay tuned to future issues of CoffeeTalk for more excerpts from The Little Coffee Know-It-All.

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