How to Make Grape Vinegar

When I first stepped into the world of making my own vinegar, information and tutorials were scarce. It's an old skill, one that very few practice in the kitchen today.

Truth be told, if it wasn't for several vintage cookbooks I sourced at my local library, I myself wouldn't be making or teaching other people how to ferment fruit (or in this case, grapes) into vinegar!

That's what I'm here for today. In this tutorial, I'm going to teach you exactly what grape vinegar is and also, how to make it in your kitchen!

What Is Grape Vinegar?

Many people feel confused when it comes to grapes and the vinegar-making process. They often assume that wine vinegar and grape vinegar are one and the same. However, this just isn't true. The creation process is different for each. And the flavor profile differs greatly!

Now I'm not a wine maker, but I did do my research and this is what I discovered.

Wine Vinegar

Wine vinegar is made from finished, red or white wine. To transform wine into vinegar, all you have to do is expose it to airflow. That's right! The air in your home carries a group of natural, airborne bacteria called acetobactors. Once they are caught on the surface of the wine, they go to work, transforming the alcohol content to acetic acid.

It can take months, but eventually (thanks to airborne bacteria), wine will be converted to a very acidic, tangy, wine vinegar!

 Grape Vinegar

Grape vinegar is made from the juice of fresh pressed grapes. To make your own grape vinegar, all you need is juice, a food grade container for fermenting and a breathable, cloth cover that allows airflow to carry airborne organisms to the surface of your grape juice.

From there, the fermenting magic just happens! I dive deeper into the particulars below. All the home brewer needs to do is wait, check on the juice and troubleshoot if any issues arise. If all goes well, a fresh tasting, tangy grape vinegar is created in just a few month's time!

How to Make Grape Vinegar

Now that you understand the difference between a wine vinegar and a fresh grape vinegar, let's get into the particulars of making the latter!

Step 1: Harvest Your Grapes

When harvesting grapes for your vinegar making attempt, choose clusters that are fully ripe! These grapes will have the highest sugar content and make the most flavorful vinegar.

To the best of my knowledge, grape varieties don't matter. As long as they have natural sugar, you shouldn't have any problem fermenting their juice into vinegar.

Step 2: Extract Juice from Your Grapes

There are several ways you can extract juice from your grapes.

If you have a steam juicer, it does an excellent job.

You can use an electric juicer if you're dealing with seedless grapes (don't do it with seedy types; they'll make crazy amounts of foam).

But I actually recommend a simpler method.

Line a large kitchen bowl with a flour sack tea towel. After rinsing your grapes under running water, remove them from their stems.

Don't worry if you crush the fruit as you handle it, or if you get some small stems in the mix. It really won't affect anything!

Once you've run out of grapes or filled the bowl 2/3 of the way, it's time to break up your fruit. You can use clean hands or use an old school potato masher.

It can be a sloppy task, but once you've turned all the grapes into a juicy, pulpy mess, it's time to collect the juice! Do this by knotting the 4 corners of your cloth together.

Hang the bundle where grape juice can drip into the bowl below. And when the dripping stops? You'll have a raw grape juice, ready for fermenting!

Step 3: Place Your Juice In a Fermenting Container

Because your grape juice will eventually turn into an acidic product, it's important that you use a food grade container for the fermenting process. I like to use wide mouth glass jars and also, small Ohio stoneware crocks.

Pour your grape juice into a food safe container. And instead of putting a lid in place, cover the mouth with a cloth, paper towel or coffee filter.

Be sure to fasten it down with a rubber band or tightly tied string. This will allow airborne organism to reach the surface of the juice, all the while keeping dirt and pesky fruit flies away from your juice!

It will also allow your ferment to release carbon dioxide in the first phase of fermentation (see step 4).

Step 4: Leave It to Work In Proper Temperatures

Leave your juice to sit in a room that is no cooler than 60F (16C) and no hotter than 80F (26C). The airborne organisms responsible for converting your juice to vinegar are sensitive to temperatures.

If they are too cold, they won't go into action. And if they are too hot? The wrong organisms will take over and spoil the batch. Should your home be too warm for fermenting during the hot summer months, extract the juice, freeze it and ferment at a later date, after outdoor temperatures have cooled down.

Step 5: Let Juice Go Through 2 Fermenting Phases

As your grape juice sits, it will go through two phases of fermentation. The first is a result of natural, airborne yeasts, while the second phase takes place due to airborne bacteria. Let me give you a breakdown of how it works!

Phase 1: The Alcohol Phase

In the first stage of fermentation, the air carries natural yeasts to the surface of your ferment. Once captured, they go into action and begin consuming the natural sugars found within your grape juice.

As they feed, they convert the sugar to alcohol (the alcohol content is very low). While the yeasts do their work, they will also create and release carbon dioxide, which is another reason you want a breathable cover on your container!

The first phase of fermentation is evidenced by the tiny bubbles that appear on the walls of your fermenting container.

They may even show on the surface of your liquid, and a layer of bubbly foam may appear. If it does, you'll want to skim it off.

Oh, don't worry! It's not harmful, but it may give mold opportunity to grow and that's something you want to avoid!

After a few weeks, your fruit juice will omit a light, alcohol-like aroma. Natural yeasts will feed and thrive until they have consumed all the natural sugars in your grape juice. After this, they die off.

Phase 2: Acetic Acid Phase

Several weeks after the bubbles disappear, you'll notice a slightly sour aroma when you check your fruit juice. This is an indicator that airborne acetobactors (acetic acid bacteria) have arrived on the scene!

This group of bacteria transforms the alcohol content to acetic acid, the thing that makes vinegar what it is!

Most of the time, this stage takes 3-5x longer than the first phase. Be patient!

Step 6: How to Tell When Your Grape Vinegar is Ready

There is no sure way to tell when your grape juice has been fully converted to vinegar. You can taste it. Smell it. Guess at whether or not it's finished! But here's the best test I've found.

When your vinegar smells and tastes sour, seal 1-2 C of the liquid in a glass jar or bottle. Make sure you have a tight fitting lid (or cork) and then let it sit at the back of your kitchen counter for 2-3 days.

Break the seal. Was there a release of carbon dioxide? If so, your vinegar is still working and isn't ready to be sealed. Leave it for another 2 weeks, then test again.

No release? It's ready to be bottle (or jarred) and used!

Step 7: How to Bottle Grape Vinegar

Because vinegar is an acidic substance, it is corrosive. Be sure to store it in a food grade container! Glass is ideal. I use canning jars, old whiskey jugs and wine bottles I got at a garage sale.

Also be aware that vinegar will slowly eat away at tin or metal lids. If used, you may end up with unwanted substances in your vinegar.

When using glass canning jars for vinegar storage, I recommend buying a set of wide mouth, white canning lids. They also come in standard mouth size.

And the jugs and bottles? Well, corks will do just fine!

Step 8: Tips for Storing Grape Vinegar in Your Home

Due to it's acetic acid content, grape vinegar is a shelf stable product and needs no refrigeration. You can keep it in a kitchen cupboard. On the pantry shelf. In a cold room or root cellar.

If stored at room temperature, the flavor will start mellowing out after about 1 year. You'll lose some of the snap and zing that comes with freshly made vinegar. But that doesn't mean you still can't use it in the home!

It should keep for up to 2 years. But trust me. If you like tangy flavors, you won't be able to keep it around that long!

Where to Go For Further Help

Now I know there was a lot of information packed into this blog post! If you want a comprehensive guide on making fruit vinegars and also using them in the home, I have something for you.

I wrote an entire book on How to Make Fruit Vinegar for Beginners.

It will give you best juicing techniques for the different fruits, fermenting guidance, troubleshooting tips and recipes for using fruit vinegar in your home.

Of course, you can always leave me your questions and comments below. I'll get back to you with the best answer I have on how to make grape vinegar!