Wine Ingredients - Ghosts
Happy Halloween, everyone! In honor of one of my favorite holidays, I thought it only appropriate that we discuss one of the cheapest and most effective wine ingredients available: GHOSTS.
Okay, they don't look particularly creepy, and what are they? Ghosts, also known as yeast hulls, are the cell walls of dead yeast. And it turns out, that they contain a lot of helpful compounds that can keep your fermentation or even your malolactic conversion from stalling out.
During fermentation, yeast throw off a lot of byproducts. Mostly alcohol, CO2, and heat, but also plenty of other compounds, like the aromatics mentioned earlier this year. Some of these byproducts are toxic to yeast-- alcohol for one, but also octanoic and decanoic acids. Ghosts can help fermentation by adsorbing these acids-- essentially pulling them out of the wine, and making the environment a little more friendly to the yeast that are working there. They also provide some of the nececssary components for living yeast to build healthy cell walls-- sterols and long-chain unsaturated fatty acids. Even after alcoholic fermentation is complete, their presence helps malolactic conversion for a lot of these same reasons-- octanoic and decanoic acids are also toxic to malo bacteria, so less concentration helps the bacteria do their jobs.
There's evidence that ghosts may also help prevent certain white wines, such as Pinot Grigio and Sauvignon Blanc from turning slightly pink in bottle, and that the addition of ghosts during fermentation can help promote tartrate stability. They can even help wines that have high levels of cork taint [a compound called TCA]. Adding ghosts can help remove some of this compound from the wine.
So there you have it-- one little ingredient with a myriad of uses. I hope the ghosts that surround you today are just as helpful!