Winemaking Tips: Blending, Fining, and Filtering

It’s almost a cliché – the image of the winemaker sitting in some kind of laboratory perfecting the blend for a final wine. In truth, it’s much more hands on. Wine is made in the cellar, after all, using tried and true methods and careful handling.

For the commercial winery, the selections of barrels for blending can be very arbitrary – a final quantity taking precedence over a final quality. The micro-winery has a much greater incentive to strive for quality, having limited resources from which to create a final blend.  

The Final Blend

The concept is simple enough. Let’s say, you have three barrels of the same white wine. You used three different yeasts to ferment the sugars, one American Oak barrel, one French oak barrel, and one stainless steel barrel. One of the three barrels finished malo-lactic fermentation (MLF). One barrel did not go through MLF. One barrel never completely went dry, but did go through MLF.

Racking all three barrels would certainly make a complex wine, from the sounds of it. But would it be the best wine?

A bench trial (aka tasting) suggests that two barrels and ten gallons of another are to be combined into the final wine. The quantity is racked (drawn off the lees) to a container. After a gentle mix and final tasting, the wine appears to be what you thought it should be. But what happens now? How should you prepare it for bottling?

The next steps take us back to the lab for some simple analysis of the wine’s SO2 (sulfite levels) and pH (acid levels). A simple countertop kit can measure both SO2 and pH. An off-site laboratory can do the work for you – at a cost. (*One good website with winemaking tips is www.Vinoenology.com)

First thing is first. An addition of sulfur should be made to protect the wine from oxygen. If possible, any open space (ullage) above the surface of the wine should be sparged with gas. Nitrogen and Argon are great for sparging tanks, barrels, and bottles.

Chilling the wine at this time can also help the subsequent fining and filtering process. Simple tank attachments or wine inserts that circulate cool water can do the trick, but so can an airtight room and an air conditioner (ie; a cellar or garage). The idea is to maintain a cool temperature to help any final colloids settle out. It also slows any microbial spoilage, much like refrigeration does for food.