How to Remove Green Stains from Your Mate Gourd: Expert Tips

There are many myths surrounding stains in yerba mate gourds. One of the most widespread is that any stain of unusual color or texture is a sign of mold or spoilage. However, green or black stains are natural and beneficial, enriching the flavor of the yerba mate over time.

If you've noticed green or black spots inside your gourd, you might be worried. Is it mold? Is your gourd still usable? Rest assured, these spots are not only natural, but they also play an essential role in the yerba mate experience.

To understand the origin of the stains in your gourd, it's essential to look at tannins. These natural compounds found in yerba mate leaves are responsible for the gradual discoloration of the gourd 's interior. As the yerba mate steeps, the tannins permeate the gourd's walls, forming green stains that gradually turn black over time.

Beyond their aesthetic appeal, these stains play a crucial role in enhancing the flavor of your yerba mate . Just like Japanese stoneware teapots , which are renowned for absorbing the flavors of brewed teas over time, yerba mate gourds infused with tannins contribute to enriching the flavor of each infusion. This natural flavor enhancement process is something to celebrate, not fear.

Another benefit of the tannins in yerba mate is their protective effect on the gourd . As the tannins accumulate, they create a protective layer, reducing the likelihood of mold growth. This protective layer also smooths the interior, allowing your gourd to dry more quickly. All positives !

Green stain after dredging

Natural gourds , made from squash , are all unique and can react in completely different ways.

Some gourds will develop green coloration which will then turn black over time. Others will develop a black coloration directly.

As you've probably guessed, the black spots are exactly the same as the green spots , as we saw earlier. They are not mold at all, but tannins. So there's absolutely no risk to your gourd or your health!

Green and black stain due to tannins

It is essential to know how to identify mold to keep your gourd in good condition. Unlike natural stains, mold appears as white marks or filaments , often fuzzy or cottony to the touch . This type of contamination can occur if the gourd is not properly dried after cleaning and in the first few days of its life, or if it is stored in humid conditions.

The distinction between natural stains and mold is crucial. Natural stains caused by tannins are usually green or black and blend evenly into the inner surface of the gourd. In contrast, mold often appears in separate patches or clumps and may be accompanied by an unpleasant odor .

Prevention is the best strategy to avoid mold growth. This involves thoroughly drying your gourd after each use and storing it in a dry, well-ventilated place. Additionally, it is recommended to empty and rinse the gourd to remove yerba mate residue and prevent mold growth after each use.

Mold in a gourd used for maté

1. Rapid identification: The key to effectively eliminating mold is to detect it quickly. The sooner it is identified, the easier it will be to remove.

2. Partial cleaning: If the mold hasn't spread throughout the entire interior, you can remove it by gently scraping the affected areas with a spoon. Then, rinse the gourd with hot water (90°C).

3. Pre-treatment: Before curing, it is strongly recommended to apply a mixture of lemon, white vinegar, and hot water (90°C). Leave this solution to work for 2 to 4 hours.

4. Complete stripping for extensive mold: If the mold has invaded the entire interior surface, a complete stripping will be necessary.

Maintaining a yerba mate gourd in good condition requires some care, especially during its initial use . This includes cleaning it after each use to remove yerba mate residue and prevent moisture buildup , which can encourage mold growth. Use lukewarm water to clean the inside of the gourd, then allow it to air dry completely.

Drying is a crucial step in caring for your gourd. After cleaning, turn the gourd upside down and allow it to drain to prevent water from pooling at the bottom. Then, let it dry in a well-ventilated area in its normal position . Avoid placing it in humid environments or turning it upside down after cleaning, as this can create an environment conducive to mold growth.

To prolong the life of your gourd, it is recommended to avoid using harsh detergents or soaps that could alter the taste of the yerba mate or damage the gourd. Aside from that, our gourds are made from the finest materials and are designed to last. In fact, we guarantee them for a minimum of 5 years !

For more tips on caring for your gourd and bombilla , we have an article on the subject!

The beginning of the effects of tannins on a natural gourd