Issue link: http://winesandvines.uberflip.com/i/804714
64 WINES&VINES April 2017 installed, these tanks may be gor- geous pieces that are impressive in size and shape. But is their util- ity based on the egg shape, or is it because they are constructed with concrete? Are these tanks going to become the next new standard in winemaking? Are there other materials that will provide the benefits without the very real obstacles presented by concrete tanks? The first benefit of concrete is its mass, which also is its first nega- tive aspect. The mass of concrete provides one of the important re- quirements for good winemaking, which is long, slow changes in temperature. But because of the tank's weight, a winery shouldn't plan on moving it very often. One major concern is that after use, cleaning concrete needs to be done carefully. As indicated above, hot water is not recommended, especially if there are any metal parts imbedded or attached to the tanks. The tank can crack if too great a temperature difference oc- curs between metal and concrete. Aggressive cleaning measures such as power washers or high-intensity nozzle-cleaning balls cannot be used. Even strong bristled brushes can create problems on tank sur- faces. Instead, alkaline cleaners such as peroxycarbonate are fre- quently used. Concrete egg tanks are prob- ably best suited for wines whose style excludes contact with oak and for those that would benefit from micro-oxygenation. Wines requiring no oxygenation usu- ally are stored in stainless steel. After storage in stainless steel, the fruit is brighter and more true to that naturally expressed by the wine. Some have de- scribed that impression as less complex, but I don't agree with that assessment. If a wine is ex- pressing only a single fruit note such as pear or apple, that is an example of a simple wine. Grape wines, unlike other fruit wines, are not by nature single- note wines. When made well, there may be an emphasis on one note above another, but in general they have many complex layers of fruit components expressed in any one wine. A winemaker mixes these notes and builds complexity. The aging process changes the fruit to more oxidative compo- nents, which alters the wine's style. So choosing concrete not only adds the oxidative compo- nent but the surface material may give a stony impression from the concrete. In other words, the tank provides another tool to get to the winemaker's stylistic goal. What other materials can be used for tank construction if the goal is a wine produced in a bar- rel-like experience without oak contact? A winemaker cannot be sure there will be no wood flavor imparted even in neutral barrels because, in most cases, these bar- rels have some wood flavors, just less than needed for traditionally oaked wines. One alternative is a plastic tank produced by Flextank USA to allow micro-oxygenation through the plastic. About five years ago, the company designed an 850-liter egg-shaped tank called the Apollo that had the oxygen transport of an oak barrel, an 18-inch manway and valves at the bottom. The goal was to offer an alternative to fer- mentation in MacroBins, but with- out the impediments of concrete. The Apollo eggs are light, have a smooth inside surface, can be sani- tized with just about any material commonly used in wineries and are a fraction of the cost of other egg-shaped tanks. The downside is they don't have the visual appeal of the more massive concrete tanks or sleek ceramic ones. Comparing fermentation in MacroBins vs. the Apollo egg During the 2016 harvest I had the opportunity to compare the fer- mentation of Chambourcin grapes in two short (half-ton) MacroBins, one insulated and one not insu- lated, and in an Apollo egg. Mac- roBins are routinely used for fermentation of small lots of about 1 ton or less. Egg-shaped tanks have been proven to pro- vide a superior fermentation regi- men compared to several other methods with little or no extra work or equipment needed. I ran side-by-side fermenta- tions of the same amount of fruit in the two MacroBins and the Apollo tank. The uninsulated WINEMAKING