Have you ever been just sitting there enjoying a nice glass of wine, minding your own business, and BAM, you get a mouth full of crud? What’s up with that!? Well I’ll tell you what’s up with that, you just got a mouth full of Lees!
First, let’s put away some fears and popular misconceptions. First, lees are not dangerous. In fact, they demonstrate better quality of the wine and add flavor. However, they themselves taste terrible, so I suggest you don’t drink them!
There are different kinds of sediment that form in wine. Sediment forms naturally during both the fermentation process and while maturing in the bottle. Some wines are more likely to produce sediment that others; Garnacha in my experience is a notorious culprit for sediment.
The initial sediment forms during fermentation. It consists of dead yeast cells, proteins, stems, bits of skin and other solid matter that settles to the bottom of the formation tanks. Wine is left with the lees for some time so it can develop more character, color, and complexity. This is why winemakers make the big bucks, because if they allow the wine to sit too long with the lees some bad taste can develop. It takes years of experience to learn the best method.
The initial lees are removed in the “clarification” process. The wine is filtered while being transferred from the fermentation tanks to the aging casts or tanks. In the aging casts more or less sediment can form, which is why the wine is often transferred and filtered additional times. This is all up to the winemaker and depending on what they are trying to accomplish. The more the wine is left in contact with the lees at each stage the better the color, character and complexity the wine will have. Or it could potentially ruin the whole lot!
The sediment which occurs in red wine develops while in the bottle, and is formed by the tannins and other solids–most often the skin of the grapes–that gradually fall to the bottom of the bottle (or the side of the bottle if you are storing it properly.) The presence of this material is good for the wine but not for the drinker, it’s not going to hurt you but is just nasty to look at, and the foul taste the sediment has can give you a negative opinion of the wine.
Here’s the cure, get yourself a wine filter. A coffee filter will work just as well as the specialized items you can buy in store, but after filtering the wine carefully decanter it before serving. Another option, though unacceptable as far as I am concerned, is leaving the last inch of wine in the bottle. I say hell no to that! My opinion is to make sure you always get the last glass from the bottle, just be very careful with your last sip!