Dover Canyon Winery

CQ2: What does it mean to 'filter' or 'fine' a wine?

 

Today's customer question:  What does it mean to 'filter' or 'fine' a wine? 

What is filtering?

Filtration makes a wine brighter and clearer by removing excess sediment and haze. Some wineries may decide not to filter their wines because they feel that the unfiltered wines taste better and have superior mouthfeel. There is no single correct answer; winemakers decide for themselves what is right for their product. Some of our red wines are filtered; some are not. Our wine labels and our website wine profiles indicate when a wine is unfiltered and unfined.

Filtering can also remove microbial problems and bacteria that might multiply in the wine after bottling, causing off aromas or secondary fermentations. Wines containing residual sugar should always be sterile-filtered to prevent fermentation as should any wines containing malic acid—both sugar and malic are high energy food sources for microbes. This means that pretty much all white wines should probably be sterile-filtered before bottling, and sterile-bottled (sterile filtration on the bottling line).

Modern cross-flow filters are extremely gentle and cool, efficient (you can walk away from them while they’re operating and they don’t break down as often) and they are a great choice for "green" and sustainable-model wineries. Unlike the old pad filters, where wine is forced through a filtration medium like a paper pad or a cake of diatomaceous earth, cross-flow filtration moves the wine across a ceramic membrane, where it is essentially "pulled through" as filtered product. There are no used cellulose pads, DE (a hard-shelled algae), or crystalline silica to dispose of.

CQ1: Attack of the Drosophila! Do Fruit Flies Ruin the Taste of Wine?

Welcome to the first in our 'Customer Question' series.  Today's question:  Do fruit flies ruin the taste of wine?

Indeed they do.  And quickly.  If you find a fruit fly in your glass, fish it out or dump the wine immediately.  Aside from the unpleasant prospect of swallowing a bug, the alcohol in the wine softens the fly's body and it releases a nasty-smelling enzyme into the wine.

If you have never recognized the smell of drosophila melanogaster, just pour 2 oz. of wine into a glass, set it out,  and wait for the little buggers to fall in.  While they are drowning, pour another 2 oz. into a fresh glass.  Smell and taste the fresh glass.  Then smell the drosophila glass.  Once you learn to detect that aroma, you will know it anywhere.  I can smell one fly in a bottle of wine, in the dark. 

During harvest, wineries are heavily populated with fruit flies.  Thousands of them will congregate around fermentors, tanks, and equipment.  According to LiveScience (How Fruit Flies Find Your Wine), they can find wine or fermenting juice from half a mile away.   This is one of many reasons that constant hygiene is important in a winery.  The CO2 rising off fermenting must provides a blanket of gas that deters fruit flies from setting foot on fermenting fruit, but few winemakers trust that to last long—as the wine approaches dryness, the fermentation slows, and the blanket of gas decreases.  Our fermentation tanks have custom built covers that fit tightly and can be quickly open and closed.  Macrobins, which wineries use for picking and fermentation, can be ordered with covers, but the covers do not fit tightly at all and are, in our estimation, worthless for keeping drosophila at bay.   Our choice, and one that is popular at many wineries, are simple cotton sheets.  They provide a fly-proof seal, are easy to remove and replace during the interminable thrice-a-day punchdowns, and can easily be cleaned and stored at the end of the season. 

When visiting a winery during harvest, there a couple of things to watch for ...