Occasionally you may come across a bottle of wine that contains tiny crystal shards that could appear as tiny pieces of broken glass. These are tartrates that are often referred to as wine diamonds. Although they may cause a slight gritty texture on your tongue, they are harmless and safe to consume.

These wine diamonds may occur if the wine has been exposed to temperatures below 4°C, when potassium and tartaric acid, both naturally occurring products of grapes, bind together to form a crystal.

Tartaric acid is used to maintain a wine’s body, character and colour but many wines contain a surplus of the acid, which accounts for the appearance of the wine diamonds.  Potassium, which is another big component in wine, binds with the acid and creates a salt called tartaric bisulfate, which separates from the wine and creates the crystals that are found at the bottom of the wine bottle or on the underside of the cork.

The colour of these crystals is dependent on the pigment of the wine. In red wine they will often appear brown or dark red. In white wines they will often look brownish or resemble glass.

It is difficult to predict which wines will have high levels of tartaric acid and thus have wine crystals.  Weather, region, soil nutrients and grape varieties all play a role in determining the amounts of acid present in a particular grape.

Older wines are more likely to form crystals or sediment once the cork is removed. As wines are constantly evolving during the aging process, elements within the wine are constantly interacting with each other. As such, some chemical bonds that are formed in the bottle are denser than the wine itself, causing them to sink to the bottom of the bottle. This is part of the aging process.

The presence of wine diamonds is considered by many winemakers as a sign of high quality because it means that the wine was not over processed.

Although wine diamonds may leave a slight gritty texture on your tongue, they do not impact the taste of the wine nor do they pose a health risk.  They are completely safe to drink.

If you prefer not to serve wine crystals in your wine you can decant the wine by simply pouring the wine through a wine strainer or cheesecloth into a wine decanter.

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Corks have been the traditional choice since the 1400’s for preserving wine. Cork bark is one of the few natural products that is malleable enough to hold the contents inside a glass bottle.  However, today there is great debate as to whether cork is actually the best way to preserve wine.  The most prominent opponent is the screw cap.

The pro cork side of the debate usually begins with the fact that tradition dictates that cork is the way to go.  It has been in use for hundreds of years.  Screw caps on the other hand are a 20^th Century invention.  

For many of the more mature members of our society there is a sense of enchantment in maintaining tradition, including the ritual of uncorking a bottle of wine, which adds to the enjoyment and experience.

Cork bark is a natural ingredient, as well as a renewable resource. Cork is harvested from the bark of cork trees, which continually replenish themselves.

One of the properties of cork is that it does not have a completely airtight seal, which allows the wine to slowly oxidize in the bottle. This oxidization allows the wine to continue to age while it sits in the cellar, developing more complex flavours over time.

The down side of using cork is that cork allows cork taint, otherwise known as TCA or Trichloroanisole, a flaw that can happen when a wine is exposed to a particular yeast during production. If you’ve ever swirled and sniffed a glass of wine and smelled something like wet dog, then you have experienced cork taint. Because corks are permeable, bottles sealed by a cork can be vulnerable to damage.

Another downside to cork is the cost as cork is more expensive than screw caps.

Finally, there is the irritation you feel when the cork breaks off or crumbles into your wine when you try to open the bottle.  To help prevent this from happening, the bottles need to be stored horizontally in order to keep the corks moist.

In the past, screw caps were associated with cheaper wines since they are less expensive than corks and were the obvious choice for budget-friendly wines. However, those days are long gone. Screw caps have their own benefits, so some high-end wineries have abandoned the cork. Some winemakers even prefer them to cork.

Screw caps do not allow TCA to occur in the wine after bottling. This doesn’t mean the wine is always free of TCA, since it can be exposed prior to bottling, but it does mean if it hasn’t happened before bottling there is no chance of exposure until it is opened.

Screw caps are much easier to open. A cork screw is not required so that means one less thing to pack when travelling.

On the down side, the airtight protection that is provided by a screw cap prevents the wine from breathing and slows down the aging process.

Also, while screw caps are recyclable they are neither biodegradable nor are they made from a renewable resource.  They typically include PVDC plastic which is made from petroleum, making them a far less eco-friendly option.

Ongoing innovation in wine packaging means that natural cork and screw caps are not the only two options for bottle enclosure and storage. Plastic, can, cardboard and plant-based polymer cork are now being introduced into the marketplace.

While natural cork adds character, heritage and custom to your wine experience but is not necessarily a reflection of quality. Screw caps are a convenient modern option, but they have their own drawbacks.

You will have to decide for yourself which you prefer. Personally, it is the wine itself that determines whether I buy it, not whether it is sealed with a cork or a screw cap.

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