Basil Turning Black in Freezer: Why and How To Prevent

Many people believe that freezing is the most effective way to keep basil fresh for longer periods of time. While it may appear to be a straightforward and convenient technique, it should be noted that freezing basil requires more effort than simply putting the leaves in the freezer.

Does basil turn black in the freezer? Frozen basil does have the tendency to discolor or turn black. This occurs due to a process called oxidization and is the result of enzyme deterioration and a release of melanin. Fortunately, this is only superficial, and affected basil can still be part of a delicious, healthy meal.

There are a few very handy tips for keeping that beautiful green color of basil and avoiding brown or blackened leaves. Read on below for our best tips on how to preserve basil.

How To Keep Basil Leaves From Turning Black in Freezer

To keep basil leaves from turning black in the freezer, we must protect them by creating a layer around them. This is best achieved by using high-quality olive oil.

Why Does Basil Turn Black When Frozen?

Basil turns black, both at room temperature and when frozen, for the same reason that fruits such as apples and pears do — oxidization. This is a chemical process where cells exposed to oxygen break down and produce a dark-colored pigment. It’s nothing to worry about, but for many of us, it does look less than appetizing. 

Can You Use Basil When It Turns Black?

Most definitely! Basil that has turned black can still be used in any cooked dishes, like pasta sauce for example. Black leaves that retain their shape are fine to use, but when leaves turn yellow or go mushy, be aware as this means you should throw them out.

How To Freeze Basil Without It Turning Black

As we have discovered, basil turns black from the process of oxidation caused by exposure to air. To stop this, we must simply find something to use as a barrier between the herb and the oxygen.

Make Pesto and Freeze

Making pesto ahead of time is a real “thank goodness” moment for those times when we have forgotten to buy that key ingredient or are simply looking for a fast, healthy dinner or lunch option. 

To freeze pesto, simply make the recipe of your choice (find delicious and healthy recipes here), and then portion it into freezer bags or ice-cube trays. When needed, retrieve portions, and thaw in a refrigerator for around 10 hours, or for immediate use, place into a bag and then into hot water.

Freeze in Olive Oil

Olive oil is a great inhibitor of oxidation and has been used for thousands of years as a natural food preservative. For this method, either place whole or roughly chopped leaves into enough olive oil to completely coat all surfaces. Ice-cube trays are great for this.

Freeze as Basil Paste

Basil paste is a fine and concentrated product. For this, finely chop basil, and add just enough oil to create a moldable paste. About 1 teaspoon of oil to 2 tablespoons of basil should do it. This is a good option for those who want less oil in their final product.

How To Use Frozen Basil

Frozen basil has a large variety of different applications and is almost as versatile as the fresh product. Of course, it is a fantastic addition to most one-pot dishes and can simply be added in its frozen state to sauces and gravies, soups, and casseroles. It can also be thawed relatively quickly in freezer bags placed into hot water or blended and shaken in a jar until thawed. This way it can be used immediately for dressings.

Additional Ways To Preserve Basil

If freezing isn’t your preferred method or you would like to have a product that can be taken on trips away from home like camping, barbecues, or picnics, then canning could be a good alternative. 

For this, simply make a pesto or basil and olive oil mixture, and follow these canning instructions. One drawback of this method is that it is quite involved for beginners and can be a big process if you only have enough basil for one or two jars.

Alternatively, salt is also a wonderful preservative. Finely chop basil leaves and stalks, and mix a 3-to-1 basil-to-salt ratio. This will give you incredibly potent, flavorful, and long-lasting basil that can be stored at room temperature. 

Of course, you can always dry your basil leaves, which will give you a higher-quality cooking herb than you can find at supermarkets. The drawback here is that you lose much of that fresh, aromatic basil flavor.

Related Questions:

How Long Is Frozen Basil Good For?

Frozen basil can be stored for a very long time without any worry about food safety. However, it should be consumed within about three to six months as after this time, it will lose some of its flavor.

Can I Freeze Basil Leaves Whole?

Yes, you can certainly freeze basil leaves whole, and this might be a good option for those wishing to preserve the herb for a short time, around two weeks or so.

How Much Basil Paste Equals Fresh Leaves?

Usually, around one packed cup of basil leaves will yield around ¼ cup of basil puree.


Basil is a wonderful herb to use fresh in an endless amount of recipes. We hope that this little compilation of long-lasting storage methods has given you a way to enjoy this herb virtually on demand.