Did you know that wine may contain surprisingly many potential allergens? Acetaldehyde and biogenic amines, which can potentially cause headaches, may be present in any wine regardless of type or production method. On the other hand, casein and egg whites are substances that may only be found in wines meeting certain specific conditions.
Wine is commonly perceived as being made solely from grapes, leading people to believe there are no allergy concerns beyond alcohol itself. However, the reality is somewhat different from this understanding. This article explores the relationship between wine and allergies, a topic that remains relatively unknown to the general public.
Wine and Allergens
An allergen is a substance that causes allergic reactions. Among the allergens found in wine, sulfur dioxide, known by the name of antioxidant, is famous. This chemical substance, also denoted as SO₂, has become one of the wine industry's greatest villains due to the mistaken popular belief that it causes headaches.
Sulfur dioxide is not a component derived from grapes. Wine may contain allergens resulting from artificial additives that are not derived from the grape raw material. A representative example of this is eggs. Wine may contain egg whites.
"What? Eggs in wine? Egg whites??" some of you might be thinking. However, for those familiar with the story behind the origin of canelé, the popular traditional French pastry, this might seem like a more familiar topic.
In any case, egg white is also one of the allergens that may be introduced into wine as a type of additive. In Europe and many other countries, it is mandatory to indicate this information on wine labels as a warning about potential health risks from allergies.
This article explains why allergens may enter wine from a winemaking perspective. Why might egg whites, which seem to have no connection to wine, potentially be present in wine?
Why Egg Whites Enter Wine
Wine is, in principle, an alcoholic beverage made solely from grapes as raw material. However, various quality improvement methods have been considered and actually implemented in winemaking practices since ancient times to "achieve higher quality finishes." These methods and types are diverse, ranging from sugar added to increase alcohol content and yeast added for fermentation, to winemaking tannins and tartaric acid.
Among these substances is a group called fining agents. Fining agents are, as their name indicates, additives used to clarify wine—that is, to remove cloudiness from wine and make it transparent. The egg whites that became a topic of discussion in the series of Twitter posts are one of these fining agents and have been used traditionally.
Wine naturally contains proteins derived from harvested grapes, in addition to artificially added substances. These proteins sometimes become the cause of wine cloudiness. Proteins contained in wine precipitate as insoluble colloids by binding with polyphenols and metals also contained in grapes. These colloids float in the bottle like white haze.
Egg whites are used to remove polyphenols, one of the substances that cause wine cloudiness. Since it's unpredictable when polyphenols might bind and cloud the wine if left alone, the proactive approach is to add egg whites to wine, artificially causing them to bind with polyphenols, and then remove them before bottling. Egg whites are also used as a means to remove excessive tannins in red wine production.
However, unlike in the past, modern winemaking facilities don't present scenes where winery workers crack large quantities of eggshells, carefully separate egg yolks from egg whites, add only the egg whites to wine, and then have staff members enjoy the egg yolks.
So how do egg whites enter wine? To explain this, we need to deepen our understanding of what "egg whites" actually are.
What Are "Egg Whites"?
Egg whites are often described as being used as fining agents for wine. However, this description is somewhat misleading. Writing "egg whites" in Japanese specifically and limitedly suggests "the white part of eggs," which prevents awareness of other possibilities. In this context, "egg whites" refers to "proteins as amino acid compounds."
The important point is that protein itself serves as a fining agent, not that the fining agent must necessarily be egg whites. There is actually no meaningful reason to focus exclusively on "egg whites."
The tweet by Mr. Noda mentioned earlier refers to "albumin residue." Albumin is an egg-derived protein. Focusing only on this might lead one to think that people with egg allergies cannot drink wine, but those with milk allergies are fine. However, in some cases, the protein used for clarification could potentially be derived from milk.
Wine and Proteins
Proteins are compounds consisting of approximately 100 to 30,000 amino acids bonded together. In winemaking, enzymes such as lysozyme are also formed based on such proteins. What's important as fining agents is these proteins, which are not necessarily limited to egg-derived ones.
Proteins are generally classified according to their origin as follows:
- Milk-derived: Casein
- Egg-derived: Albumin
- Leather and glue-derived: Collagen
- Hair and horn-derived: Keratin
Among animal-derived proteins that may be used in winemaking, casein and albumin are the main ones. Recently, from a vegan compatibility perspective, proteins derived from fish and plants are increasingly being used. Furthermore, gelatin made by processing collagen is also utilized as a wine fining agent.
This means that the types of proteins contained in wines that use fining agents during production are not fixed. Any type of protein may potentially be present.
Summary: Unfined Does Not Mean Protein-Free
The cause of such animal proteins being contained in wine is the fining process. If protein-based fining operations are not performed during winemaking, the possibility of allergens derived from animal proteins being contained in wine is eliminated.
However, fining agents that may be used in wine production processes are not limited to proteins. Sometimes fining operations are performed to remove proteins contained in wine. This means that unfined wines have two meanings:
- Wines that do not contain animal proteins
- Wines that retain proteins derived from sources other than fining agents without removal
Most proteins that become allergens are animal proteins such as casein and albumin. Therefore, it is not wrong for people with milk or egg allergies to inquire about "whether fining was performed" during wine production as a precaution. If "fining" has not been performed, casein or albumin will not be contained in the wine in most cases.
On the other hand, it should be understood that the perception that "unfined wines contain no proteins" is incorrect. "Unfined" conversely suggests that the wine contains proteins.
When there are allergy concerns, rather than making broad inquiries about "whether fining was performed," it is necessary to target the specific components you are allergic to and inquire whether those components were used as fining agents and whether measurements of final residual concentrations in the wine have been conducted.
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