Think Wine is Just Grape Juice and Yeast. Think Again!

Photo by Roberta Sorge on Unsplash

What is more natural than a glass of wine?

Grow some grape vines, wait for them to produce grapes, harvest the grape bunches, de-stem them (sometimes), crush them to produce juice, leave the crushed grapes in contact with the juice to create color (in the case of red wines and rosé) and then rely on natural yeasts or added yeast to convert the natural sugars in the grape juice to alcohol and, voilà, - you have wine! It’s just that simple, right?

Well, wine isn’t always that simple. While some wines are indeed produced with these simple steps and ingredients, there are some other ingredients that can be used in the winemaking process. And, the only two ingredients that are required to appear on a wine label are the alcohol content and if it contains sulfites.

Here’s a few of the other ingredients that may be used in wine making or remain in a wine:

• Added Yeast Nutrients and Enzymes

  • Yeast nutrients are used to speed up the process of fermentation.

• Potassium Sorbate and Potassium Metabisultite

  • Both of these ingredients are used to guard against bacteria and protect the yeast from spoiling, and are commonly used together during the fermentation process to help the yeast ferment efficiently while improving the overall flavor.

• Acid, Sugar, and Tannin Additions

  • Adding acid will decrease the pH and increase the total acidity of the wine to ensure it is in overall balance

  • Adding sugar before or during fermentation can help boost the alcohol content. The process is called ‘chaptalization’ and also assists the yeast during the fermentation process.

  • Powdered tannins may be added early in the process to help add balance

• Acid Reducers

  • Calcium carbonate is used to reduce the acidity of the finished wine, and is sometimes added if the grapes have had trouble ripening. It’s usually added before or at the start of fermentation, so it doesn’t impact on the aroma of the wine.

  • Potassium Bicarbonate is also used to help lower the acidity

• Oak and Oak Chips, Powders, and Granules

  • Winemakers rely on oak barrels to flavor wine with notes of vanilla or subtle spices,

  • If the wine doesn’t come into direct contact with wood (i.e., stainless steel tanks), some producers will add oak chips, powders or staves to add oak flavors.

• Stabilizers and Anti-Sediment Additions

  • Potassium bitartrate is used as a seeding agent to promote tartrate precipitation during cold stabilization

  • Urease is added to reduce the level of urea in wines, when this is excessive, in order to avoid the formation of ethyl carbamate during aging.  The enzyme transforms urea into ammonia and carbon dioxide.

• Fining Agents

  • Fining agents are used for clarifying wine. These agents, such as bentonite (powdered clay), isinglass (fish bladder), casein (milk protein), gelatin or egg whites, combine with sediment particles and cause them to settle to the bottom of the vessel, where they can be easily removed before the wine is bottled.

• Grape Concentrate

  • Grape juice concentrate is sometimes included to boost the color of red wine and add a bit of sugar to smooth out the mouthfeel.

• Coloring Agents or Color Stabilizers

  • Coloring agents may be used to deepen the color of red wines, or to add ‘blush’ to whites

  • Stabilizers ensure the wine’s color does not change during fermentation and aging

• Dimethyl Di-carbonate, Ammonium Phosphate and Di-ammonium Phosphates

  • Dimethyl di-carbonate is used to stabilize wine by preventing microbial spoilage

  • Di-ammonium Phosphate is used to speed up the fermentation process

• Sulfur Dioxide

  • Usually listed as ‘sulfites’. It’s used to preserve the grapes and prevent oxidation during the winemaking process.

• Preservatives and Antibacterial Agents (e.g., potassium sorbate, dimethyl dicarbonate, sorbic acid, copper sulfate)

  • Preservative such as potassium sorbate or sorbic acid are used to 'stabilize' a wine and prevent a renewed fermentation by inhibiting the yeast cell from being able to multiply, grow and begin a new fermentation.

  • Dimethyl dicarbonate is used to stabilize the wine by preventing microbial spoilage

• Alcohol

  • Adding alcohol, usually from another grape-derived spirit such as brandy, is called fortification. Since yeast naturally dies at 15% ABV, addition of extra alcohol will push the alcohol concentration of a wine over the 15% mark.

  • Alcohol is added to “Fortified” wines such as Port, Sherry, Madeira, Marsala and Vermouth

Your Oaked Wine May Have Never Been in an Oak Barrel!

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Oak is used extensively in winemaking during fermentation and aging. It can add flavor compounds – including aromas of vanilla, clove, smoke and coconut.

Oak barrels also allow the slow ingress of oxygen – a process which makes wine taste smoother and less astringent.

Oak barrels also provide a great environment for certain reactions to occur, specifically Malolactic Conversion.

While oak wine barrels are made of French, American and Hungarian oak, they are all expensive. And they only impart flavor to wines during their first two to three uses, after which they are considered ‘neutral.’

So, to get the oak flavors without all the cost, some wines are made with oak chips, oak cubes, oak staves and even oak powder. Using these oak barrel alternatives allows wine makers to use less expensive containers (e.g., Stainless Steel tanks) and still get the desired oak flavors. After the wine has had the necessary time in contact with the chips, cubes, staves or powder, they are physically removed or filtered out and consumers never know the difference.

This may seem ‘wrong’ to many wine purists, but it is allowing winemakers to produce oak flavors in their wines at considerably lower costs. And, studies have been done that show consumers can’t tell the difference. Wine labels don’t tell us the difference, but if oak alternatives are used, and you enjoy the wine, then I’d say the winemaker succeeded! Cheers!