Is Wine Gluten-Free…Or Not?

Published February 8, 2021

Spoiler Alert: Wine is considered safe to include in a gluten-free diet by most people in the gluten-free community. This article addresses the common questions that come up regarding wine and gluten. 

Want to enjoy a glass of wine but wondering if it is gluten-free? Wine is made of fermented grapes – which are naturally gluten-free, but does that mean wine is always gluten-free?  

To understand why there are questions around the gluten-free nature of wine, it is important to know more about the winemaking process. We’ve put together some frequently asked questions about wine, winemaking, and gluten to shed some light on the subject.  

Q: Is wine gluten-free?

A: Like any agricultural product that goes through various stages of processing and handling, there can be a risk of accidental cross-contact with gluten along the way, from vineyard to a bottle of wine. Check out our article about cross-contact and “agricultural commingling” that explains the various ways gluten might come into contact with non-gluten foods. 

The answer to the question – “Is wine gluten-free?” – is not a clear “yes” or “no,” but more like “probably” or “usually.” There is no industry-wide testing that definitively proves that wine is always gluten-free. The Alcohol and Tobacco Tax and Trade Bureau (TTB) recently (October 2020) changed their rules to allow gluten-free to be on wine labels since wine is fermented from naturally gluten-free grapes. Wine companies are slowly starting to invest in third-party gluten-free certification. You may begin to see “gluten-free’ on wine labels in the near future for the added assurance that it is gluten-free. 

Q: At what stage could gluten be accidentally introduced into wine?

A: The more steps an agricultural food product takes to get from farm to shelf, the more opportunities for gluten could enter the picture. Some stages of winemaking pose greater opportunities for gluten cross-contact than others, although the risk appears to be low in most areas.  

There are five basic steps to winemaking: Harvesting; Crushing and Pressing; Fermentation; Clarification or Fining; and Aging and Bottling. We’ve broken down each stage below and included what we know about the potential for gluten cross-contact. 

1. Harvesting – Wine grapes are often grown on land where grains used to be grown a century ago. The chances of gluten being present in the soil is negligible to none. In the last decade, some vineyards reintroduced grains – such as wheat, barley, rye and oats – into their vineyards to return to older farming practices in the region. Growing wine grapes and grains on the same land increases the potential risk of gluten cross-contact at the growing and harvesting stage of winemaking. Wine and grain typically do not share the same harvesting equipment or processes.
    
2. Crushing and Pressing – In modern day winemaking, wineries use crusher-destemmer machines to mash up the grapes (instead of stomping on them with bare feet) and to remove the stems from the fruit. The grapes are funneled from containers into these machines, then moved into other containers for fermentation. Typically, this equipment is not used for processing any gluten-containing items, and gluten-containing substances are not added during this process.
    
3. Fermentation – Wine is a fermented product, not distilled. If there are any traces of gluten in the grapes before reaching this stage, the fermentation process will not remove them. Check out our article, “Distillation vs. Fermentation,” for more information.
    
4. Clarification or Fining – Fining is a process that removes unwanted substances, called “colloids,” from wine. This process produces a clearer, particle–free finished product that also stabilizes the wine for longer shelf life. Fining involves adding a substance to the wine after fermentation to flush out anything that affects color, flavor, aroma, and clarity. Winemakers may use egg whites, casein, isinglass (a form of collagen derived from fish bladders), bentonite clay deposits, carbon, skim milk, animal-derived gelatin, or Polyvinylpolypyrrolidone (PVPP) for fining, all of which are gluten-free. One study in 2010 tested wheat gluten as a fining agent for red burgundy wine as a replacement for commonly-used animal by-products like gelatin. However, while gluten may have been explored as an alternative, adding gluten in fining is not a common practice in today’s winemaking. 
    
5. Aging and Bottling – Wine is aged in barrels to slowly let oxygen into the wine over time. The barrels – typically made of oak – are selected to add to the flavor of the wine. A standard oak wine barrel is made up of narrow strips or planks of wood, called staves, that are placed next to one another to form the rounded sides of the barrel. A groove, called a “croze,” is cut into the staves at the top and bottom where the flat barrel heads are fitted to create a tight seal. Traditional oak barrels and casks for wine are made by skilled craftsmen called “cooperages.” In the past, some cooperages used small amounts of flour-based paste containing gluten to create a tight seal in the croze. Winemaking has changed over the years. These days, gluten-free paraffin or barrel wax is more commonly used as a wine barrel sealant. Many wines on the market today are aged in stainless steel barrels that do not require a sealant of any kind. At the bottling stage, unless the bottler also handles gluten-containing foods on the same machines, the risks of cross-contact are extremely low. 

While there could be gluten introduced at any stage of winemaking, there is no scientific evidence proving that gluten is present in wine – or that it isn’t. Because of some of the above conditions, there could be trace amounts of gluten in some wines, but any gluten present would most likely be in amounts far lower than the FDA threshold of 20ppm. 

Read the wine label to see if they’ve specified their winemaking process or go to the wine company’s website to learn more. Many winemakers are willing to answer your questions about their practices and any potential risks of gluten if you inquire. 

Q: Are wine coolers and flavored wines gluten-free?

A: Many wine coolers are not gluten-free if they are made with a malt-base. Wine coolers were originally watered down and sugared up wine blends. In 1991, the U.S. Congress raised the excise tax on wine to five times its original price, prompting wine cooler makers to seek alternative ingredients, resorting to a malt base and other alcohols. For years, wine coolers were categorized as flavored malt beverage or FMBs. Malt is derived from barley, one of the three gluten-containing grains you should avoid if you are living gluten-free. More recently, wine cooler makers shifted back to using wine instead of malt-based additives. Check the ingredients on any wine-related product to double check what is in it. Wines with added flavoring, such as fruit flavors, could contain gluten and should be avoided.  

Q: How can I be sure that a wine is gluten-free?

A: The only way to be sure a wine is gluten-free is to look for the words “gluten-free” or a gluten-free certification mark on the label. Most wine companies have not yet sought out third-party gluten-free certification. You will probably see more wines with “gluten-free” on the labels in 2021 since the TTB changed their rulings in late 2020. We anticipate that wine companies will seek out third-party gluten-free certification to build consumer trust. 

When looking at the five stages of winemaking and the online conversations about gluten in wine, the focus seems to be on three main areas:  

1) gluten used in fining (rare, if used at all) 

2) gluten in wheat paste to seal oak barrels (replaced industry-wide with wax, so also rare, if used at all) 

3) potential cross–contact in fields or shared equipment (rare unless a vineyard specifically introduces gluten-containing grains into their growing fields alongside grapes)  

Remember, wine is considered safe to include in a gluten-free diet by most people in the gluten-free community. The only way to know for sure if a wine is totally gluten–free is through a third-party certification or a gluten-free statement on the wine label as allowed by the TTB. Most wines should be safe to drink if you have celiac disease. If you are concerned about trace amounts of gluten, contact the winemaker to learn more about their practices. 

Does Fermentation or Distillation Make a Product Gluten-Free?