Enzymes Can Improve Wine Color, Aroma, and Texture

Last updated:10/2021

Applies to: Winemakers looking to increase color extraction and enhance structure, increase aromas, or improve wine roundness. This article details which enzyme activities are suitable for each goal.

Enzymes Can Improve Wine Color

By Increasing Color Extraction and Enhancing Structure in Reds

The extraction and stabilization of color and structure molecules in red wines is a complex topic, but we do know that enzymes can play a role in improving both of these. Anthocyanins are the main compounds responsible for color in red wines. Anthocyanins are extracted from grape skins during fermentation and are color-active depending on pH but are not inherently stable on their own. Their long-term stability in wine depends on their ability to form complexes with larger molecules (like tannins). Enzymes can help increase color and color stability by increasing extraction of both anthocyanin and tannin*. While important in color stability and complexing, tannins are also a major contributor to wine structure.

Anthocyanins and tannins located within the grape skins can be released with certain enzymes, known as macerating enzymes. These enzymes degrade grape skin cell walls and will facilitate the release of both compounds. Macerating enzymes specifically include those with cellulase and hemicellulase side-activities which break down cellulose and other structural polysaccharides¹.

Enzyme preparations for color extraction and stabilization often have a mix of enzymatic activities. The way these enzyme activities work together is synergistic, not purely additive, such that gentle extraction can be achieved without overextraction. Overextraction can lead to bitterness, astringency, and harsh phenolics. We have found that a mix of enzymatic activities is beneficial for gentle extraction of color, tannin, and other compounds that contribute to structure. We recommend trialing macerating enzymes to find one that works for you.

*It is worth noting that beyond concentration of anthocyanin and tannin, there are other factors that affect the success of complexing, which is part of what makes color and color stability so complicated.

When to add enzymes for color and structure:

Macerating enzymes should be added to red fruit pre-fermentation or during fermentation.

Enzymes Can Improve Wine Aroma

By Increasing Aromas In Whites, Rosés And Fruity Reds

Aroma compounds are found in grape skins and the pectin layer immediately beneath the skins. Aroma compounds are either free (odor-active) or bound (odorless). Both types are extracted into juice via skin contact and/or pressing. Enzymes can help increase extraction of both free and bound aroma compounds and can also convert bound into free. Pectinases with β-glycosidase activity are well-suited to achieving both goals and can be used at multiple stages of the winemaking process:

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Pectinase Activity for Pre-Pressing

The pectinase activity of these enzymes makes them useful as pre-pressing, skin contact enzymes. They will break down the skins and pectin layer allowing aroma compounds to more readily extract during pressing.

This action is not compound-specific and will help release many types of free and bound aromas including terpenes, thiols, and isoprenoids. These compounds collectively contribute to aromas including fruity, floral, citrusy & spicy that help determine a grape’s varietal character.

β-glycosidase Activity for Post-Fermentation

Bound aroma compounds are odorless upon extraction into the juice and must be converted to the free form before they can contribute to wine aroma.

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Thiols are found bound to amino acids and these bonds can be cleaved by enzymes found in yeast. Terpenes and norisoprenoids, on the other hand, are found bound to sugars and these bonds can be cleaved by enzymes with β-glycosidase activity². This action is inhibited if sugar is > 50 g/L, so they work best after fermentation. Bound terpenes exist at much higher concentrations than free terpenes, so releasing them is critical to making the most of the aromatic potential of the grape.

With post-fermentation use, it is important to note that β-glycosidase activity will continue until inhibited (with a bentonite addition). These enzymes should be bench trialed or the wines should be closely monitored to determine the appropriate amount of enzyme action.

When to add enzymes for aroma:

These enzymes should be added directly to grapes (skin contact) if pectinase activity is desired, or after fermentation has completed (post-fermentation) if β-glycosidase activity is desired.

Enzymes Can Improve Wine Texture

By Increasing Wine Roundness

Polysaccharides are a class of molecules that broadly correlate to wine texture. Beneficial polysaccharides can be released into wine when yeast die and autolyze. Thus, lees aging often leads to rounder, fuller-bodied wines.

β-glucanase enzymes will break down yeast cell walls, allowing release of polysaccharides which adds mid-palate and boosts mouthfeel. Further degradation of the yeast will also lead to release of peptides and nucleotides which can increase savory or sweet characters. β-glucanases can also assist with filtration problems, particularly those related to Botrytis infection (See Enzymes Can Make Filtration Easier).

When to add enzymes for roundness:

These enzymes should be added near the end or right after fermentation but at least 4-8 weeks before bottle preparation.

Learn More

See the buying guide below for assistance in selecting Scott Labs enzymes to improve wine color, aroma, and texture.

Citations:

1. Mojsov, K., Andronikov, D., Janevski, A., Jordeva, S., & Zezova, S. (2015). Enzymes and wine: The enhanced quality and yield. Savremene Tehnologije, 4(1), 94–100. https://doi.org/10.5937/savteh1501094m
2. Liu, J., Zhu, X.-L., Ullah, N., & Tao, Y.-S. (2017). Aroma glycosides in grapes and wine. Journal of Food Science, 82(2), 248–259. https://doi.org/10.1111/1750-3841.13598