Closely related to the clarifying wine, is stabilizing it. Many of the same methods used for clarifying wine are also used to stabilize it, with a few additions.
What is an unstable wine?
By unstable we mean that the wine is susceptible to spoilage. The most common causes of spoilage are oxidation, unintentional second fermentations, and excess protein.
Spoiled wine may taste old and weak in the case of oxidation. Otherwise spoiled wine may take on a rancid or rotting flavor profile. None of these are the least bit desireable.
Except for oxidation spoilage mainly occurs due to uninvited micro-organisms. These organisms may have come in with the fruit or may have stuck around on a piece of equipment that didn’t get sanitized quite well enough.
How to Stabilize Wine
There are different stabilization methods for different types of spoilage. The simplest forms of stabilization being racking and filtering. Both serve to remove undesired yeasts and other micro-organisms.
Additionally, there are any number of chemicals that can be used to kill off these organisms so that there’s not a party in your wine after you’ve bottled it. For example sulfur-dioxide is used to kill of yeast cells to prevent a second fermentation. Bentonite is used to remove excess protein (also known as hot stablization).
Cold stabilization is when you reduce the temperature of your wine to nearly its freezing point to purposefully form tartrate crystals you can then remove through racking. These harmless crystals form when tartaric acid precipitates out of the wine. They have no effect on the flavor but they can put people off because they look like broken glass.
Oxidized wine, however, is permanently ruined. There’s no reversing the effects of too much oxygen so be sure everything is tightly sealed during the aging process.
What Methods Should I Use?
The method of stabilization you use on your wine depends largely on what issues you’re facing. By in large the best preventative stabilization method is the addition of sulfur-dioxide(SO2). Whether introduced as a gas or in tablet form this chemical kills off yeast, malolactic bacteria, and many other micro-organisms. Adding SO2 should be part of your wine making process.
Aging your wine prior to bottling will give many stability issues time to show their faces. You don’t want to find out you’ve got stability issues after you’ve bottled. Any treatments after bottling will take a lot of work and introduce far too much oxygen.
If your wine is getting cloudy or tartrate crystals are forming its time to start clarifying and stabilizing. Start out by racking and, if you’re through all your fermentations, add SO2. In the case of tartrate crystals cool your wine to near its freezing point and rack it.
After any clarification or stabilization treatments give it more time to see what happens. You may need to do more than one stabilization.
Being able to see your wine is a key element here. Aging in oak barrels can make it hard to tell what’s going on. Careful inspection with a wine thief and your test kits is your best bet.
Lastly, taste your wine before bottling. In fact you should taste your wine periodically during the entire process (except maybe during fermentation). By looking,, tasting, and testing you should be able to determine if you’ve got some micro-organism rough housing going on.
If you’ve racked a few times, added SO2 to stem off further reactions and everything looks good then you can start bottling!
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Photo by: Kyle May