What makes a vegan-friendly wine vegan? And how’s it different to conventional wine?

Consumer interest in vegan wines is growing, with vegan-friendly wines showing up in many supermarkets and Google searches for “vegan wine” soaring in recent years.

But what makes a vegan-friendly wine vegan? And how’s it different to conventional winemaking techniques?

I’m an oenology and chemistry researcher; I’ve spent years studying wine and winemaking processes. To explain the difference between vegan and non-vegan wines, I first need to walk you through the basics of conventional winemaking.

So top up your glass and let’s begin.

How conventional wine is made

In conventional winemaking, for both red and white, the grape has a long and tortuous path from the vine to the bottle.

Red wine fermentation is carried out with the skin on the grape, as this is where the molecules that contribute to colour are found.

Additions and manipulations can be extensive. Yeast is normally added in combination with diammonium phosphate, a source of nitrogen, to ensure a controlled and manageable fermentation.

Enzymes may be added, either to break down pectin (a fibre found in fruits) or to enhance flavour. Malo-lactic fermentation – where the grape’s malic acid is converted to lactic acid – is common in red wine and also used in some white wine styles.

Gross lees (waste yeast) can be removed by “racking” – which means moving wine from one vessel to another – while the smaller fine lees are removed by filtration.

Finishing the wine prior to bottling

Wines are routinely tasted prior to bottling. It’s often at this stage a decision is made the young wine may need adjustment to the palate structure.

For example, a wine may have an obvious drying effect in the mouth, known as astringency, or exhibit a slightly bitter aftertaste. This can happen when the amount of polyphenolic compounds – micronutrients that naturally occur in plants – are higher than preferred.

In red wine, polyphenolic compounds are commonly called tannins; these are macromolecules made up of carbon, oxygen and hydrogen atoms. The molecules are much smaller in white wine and, in that context, are usually referred to simply as “phenolic compounds”.

Phenolic compounds interact with proteins. Think of putting milk into a cup of strong black tea to soften the taste and give a more rounded, less bitter taste.

Winemakers will add one of the permitted protein additives after setting up a tasting trial to assess the right amount of protein to be added. This process is known in the business as “fining”.

Now here’s the problem for vegans

This is where things get problematic for vegans.

The commonly used proteins are gelatin sourced from cow or pig collagen, isinglass (from fish swim bladder), egg white or skim milk.

Each protein tends to have specific fining ability, and winemakers make decisions on which to use based on experience or advice.

Australia has comprehensive rules regarding wine labelling, including the need to specify al

Bioengineered foods served in restaurants, cafeterias and transport systems, including food trucks, are also excluded. And the standard excludes meat, poultry and eggs, as well as products that list those foods as either their first ingredient or their second ingredient after water, stock or both. It takes a 43-minute USDA webinar to explain what’s in and what’s out under this new disclosure standard.

Advocates say the standard is discriminatory because it gives food manufacturers disclosure options that can substitute for the green bioengineered seal. They include listing a phone number to call or text for information or a QR code. But critics point out that many people in the U.S. lack access to smartphones, particularly those over 65 and those earning less than $30,000 annually.

In my view, consumers who want to avoid bioengineered foods may best be served by buying products that are certified organic, which prohibits genetically modified ingredients. Or they can search for the voluntary Non- GMO Project Verified label, which features a butterfly. It was launched in 2010 and appears on tens of thousands of grocery items. Both labels indicate that a third-party inspector verified that the non- GMO standard has been met.

The new federal labeling standard came to market with little fanfare – probably because neither side in the battle over genetic modification and food sees it as a win. ■

Kathleen Merrigan, Executive Director, Swette Center for Sustainable Food Systems, Arizona State University

This article is republished from The Conversation under a Creative Commons license.