Potassium sorbate (or k-sorbate) is a common additive used in wine kits. It’s usually added in the form of a power after fermentation has completed. But what does it do? What precautions should winemakers be taking when using it? Potassium sorbate should always be used in combination with Potassium Mmetabisulphite.


WHAT DOES POTASSIUM SORBATE DO?
Potassium sorbate, a stabilizing agent, must be used with care. Simply put potassium sorbate is used to prevent spoilage by yeasts and molds in a finished wine. It does this by rendering these micro-organisms unable to reproduce.


It is added to wines that have completed fermentation to prevent spoilage but also to prevent further fermentation of sugars added after fermentation such as when you back sweeten a wine. In the case of wine kits you would add potassium sorbate prior to adding the “f-pack” (grape juice concentrate).


Usually you wouldn’t add potassium sorbate to a dry red wine because the sugars have been completely exhausted and the additive is not needed.


Potassium sorbate should always be used at the same time with potassium metabisulfite. Together they make for a rather inhospitable place for micro organisms.


The sulfites from potassium metabisulfite removes the oxygen from your wine to prevent micro-organisms from getting established while sorbic acid from potassium sorbate renders yeasts and molds unable to reproduce.

LIMITATIONS OF POTASSIUM SORBATE.
While this additive does stabilize wines it does have three distinct limitations. First, it is ineffective against bacteria.

If stray bacteria or lactic acid bacteria were to get in your wine while using only potassium sorbate it would not prevent spoilage or malolactic fermentation (as caused by lactic acid bacteria). The combination of sulfites and sorbate help reduce your risks of this as mentioned before.

The second limitation of potassium sorbate is the length of time it is effective. Once added to wine it stays in the desireable form of sorbic acid only for a short time. Over time it breaks down into ethyl sorbate which can add notes of pineapple or celery to your wine.

The change into ethyl sorbate is not preventable. By using potassium sorbate winemakers are putting a definite shelf life on their wines before they pick up these off flavors.

The third limitation is that it reacts poorly with lactic acid bacteria. According to my research it can produce strong geranium odors which most wine drinkers consider a flaw. The addition of potassium metabisulphite prevents this.

Because of these limitations many wineries do not use potassium sorbate. They opt to stabilize with sulfites only an rely on their ability to properly sanitize everything to prevent spoilage. Interestingly, wines with potassium sorbate may not be classified as organic.

PRECAUTIONS WHEN USING POTASSIUM SORBATE.
Despite these limitations kit manufacturers include potassium sorbate in their wine making kits. This is to make sure the wine is as stable as possible even if there were some equipment sanitation lapses.

Potassium sorbate should be stored in a dry area away from heat and light. Storage temperatures should not exceed 100 degrees (F).

Like many additives potassium sorbate is an eye irritant. Should you get any in your eyes flush them with water for 15 minutes and get medical attention.

Lastly, and most importantly, paper or cloths that have absorbed potassium sorbate may spontaneously ignite! So be very careful when cleaning up sorbate spills in your wine making area.

If you do spill and use paper towels or a cloth to sop it up be sure to rinse them thoroughly. I’d also be very reluctant to use this additive in a carpeted area as it would be difficult to remove it without a steam cleaner handy.

SHOULD I EVEN USE IT?
With all the potential flavor issues that potassium sorbate can cause it’s good to ask yourself if you should even use it.

On one hand if you’re new to wine making and you’re using a kit I suggest following the directions completely. Once you have a kit or two under your belt, however, then you can think about leaving it out.

If you’re working with frozen must or fresh fruit that will make a wine that can stand a little aging it’s worth considering leaving it out.

The best thing you can do though is seek experienced advice when it comes to additives.
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Potassium metabisulfite comes with just about every wine kit and is used as an additive even in wineries.  This article explores what potassium metabisulfite is and how it works. To learn how to figure out how much to add to your wine check out Adding Potassium Metabisulfite to Wine (includes a calculator).
But what does it do? What is it for? Is it safe? Let’s find out.

WHAT IS POTASSIUM METABISULPHITE
Simply put it’s an antioxidant. It slows down the aging, i.e. oxidation, of wine by removing free oxygen suspended in the wine.  Oxygen is both harmful and beneficial to wine. It is harmful in large quantities because it rapidly accelerates the aging process. However, wine starved of all oxygen can develop off flavors. The solution? Remove all oxygen suspended in the wine, bottle it, and let tiny amounts back in through natural cork closures. This is what we call micro-oxygenation.  Potassium metabisulfite is often called a stabilizer because it serves to prevent spoilage and further fermentation by removing oxygen. However, this serves another purpose it preserves the flavor and color of a wine.
An over oxidized wine can taste cooked or flabby (lacking body). Additionally, an oxidized wine turns red wines orange and eventually brown. White wines turn a golden brown color.  This additive is available in a powdered form as pictured here as well as in tablets called campden tablets (affiliate links).

HOW DOES IT WORK
Potassium metabisulfite may also be used as a sanitizing agent due to its antioxidant properties.
When you dissolve PM (K2S2O5) in water it forms three different compounds, sulfur dioxide, bisulfite, and sulfite. Each of these is able to bond with free oxygen floating around in wine. When this happens the free oxygen is no longer available to be consumed by micro-organisms.

The removal of oxygen chokes off most micro-organisms and will prevent them from reproducing. It does not, however, stop a fermentation. Yeast produces alcohol only when forced to live without oxygen but it does go on living. Read this post for more information on the how yeast is used to make wine.  By adding potassium metabisulfite after you’ve stopped fermentation completely you can then back sweeten a wine with little risk of rekindling the fermentation of newly added sugar.

COMMON MISCONCEPTIONS
Sodium Metabisulfite can be used interchangeably with potassium metabisulfite.   While they both have very similar chemical makeups the difference is that potassium metabisulfite leaves potassium behind and sodium metabisulfite leaves sodium behind.  Potassium occurs naturally in grapes and is essential to their growth. So adding a bit more potassium to the mix isn’t going to hurt anything. There’s already some in your wine.   Sodium on the other hand is not something we want to add to our wine. Can you see yourself pouring table salt into a glass of wine? No. Don’t use sodium metabisulfite.

THINGS TO BE CAREFUL FOR WHEN USING POTASSIUM METABISULPHITE.
There are a few things you should know about potassium metabisulfite before you use it again. First, the compounds it creates can be hazardous to your health in large quantities.  SO2 is a toxic gas to breath. It can cause breathing difficulties, swelling, rashes, and difficulty swallowing. If you feel any of these go for help.
Be careful not to breath the dust in or gas that is released when dissolving in water. I’d also steer clear of sipping on any samples immediately after adding this to your wine. Give it time to bond with the oxygen.  Potassium metabisulfite is a controlled substance in food and wine preservation. There are strict legal guidelines on concentrations that are allowed in the final product.  This all sounds scary and I don’t mean to come across that way but it is important to know and understand the nature of the chemicals we’re using in our wines. Wine kits and packages from winemaking stores don’t often come with any sort of precautions or warnings. So I thought I’d fill you in.  Now before you decide you’re not adding this to your wine because it’s so nasty think about this. The compounds created by dissolving potassium metabisulfite readily bond to free floating oxygen and create new compounds.  These new compounds are not nearly as scary. Even so the concentration of the new compounds in your finished wine will be so small that they will not be noticeable to the consumer.  It’s only bad for us in it’s pre-mixed state. So don’t worry. It is very beneficial to the color, flavor, and longevity of you wine.  Now that you’ve gotten a proper introduction to this additive check out, Adding Potassium Metabisulfite to Wine, which explains how to calculate the proper addition for your.  VIA FACEBOOK

SHOCKING
What is "bottle shock?" How can you tell if a wine has it?
“Bottle Shock” is a reaction that occurs in wine immediately after corking, resulting from oxygen being absorbed during the bottling process.  This small amount of oxygen introduced during this process will not usually oxidize or ruin your wine, but rather in the long run it helps during the maturation process.

Bottle Shock is characterized by muted or disjointed fruit flavors in the wine.  The wine may have a flat flavor and aroma, and may sometimes be accompanied by an off-putting odor.  Bottle Shock can also be caused if sulfur dioxide is added during the bottling process, also affecting the flavors and odor of the wine.

Bottle Shock is a temporary condition and your wine will need time to get over the shock of being transferred.  The wine must rest and recover, working inside the bottle to reach a new equilibrium.  There are no solid rules for how long the wine should rest in order for the Bottle Shock to dissipate.  Some sources say a few days of rest will cure Bottle Shock. Others state that Bottle Shock dissipates within a few weeks.

The amount of time required for the wine to rest will vary depending upon the variety of grape, vinting process, wine style, cellar conditions, size of bottle, etc.  While many variables affect the equilibrium process, usually after 8-12 weeks, the Bottle Shock will subside. 

If your wine is heavy with tannins, the Bottle Shock recovery time may be even longer. Jack Keller states that “two months is long enough, but I give Pinot Noir three just because it is PN and doesn't act like other wines.”

Bottle Shock is also sometimes referred to as “Bottle Sickness”, which more often refers to the condition resulting from shaking the wine causing any settled solids to stir up and to cloud the wine. Fragile wines shaken in travel can get bottle sickness.

I had the opportunity the other day to sample the most text book perfect example of bottling shock that I have ever seen.  So I would like to share this artical from the internet, it is a very god discription of bottling shock.