Fermenting Herbs: Step-by-Step to a Flavorful Herb Paste
Summer is the best time to enjoy fresh herbs in all their diversity. Basil on the balcony, arugula from the garden, or a bunch of parsley from the farmers' market – often more grows and ripens than can be used immediately. But instead of letting herbs wilt or freezing them, there's a particularly aromatic way to preserve them: fermentation.
With a fermented herb paste, you can transform fresh herbs into a flavorful everyday ingredient full of taste. At the same time, you'll learn the basics of fermentation and can later apply what you've learned to many other ingredients.
Fermentation of Herbs
When fermenting herbs, we harness the natural work of lactic acid bacteria. With the help of salt, an environment is created where the desired microorganisms can multiply. During fermentation, new flavors develop and the herbs are naturally preserved.
The special thing is: once you understand the technique of fermentation, you can apply it again and again – also with other herbs such as basil, parsley, dill, cilantro, mint, or seasonal herb mixtures.
Why should you ferment herbs?
Fermentation is a simple way to consciously use seasonal ingredients and preserve food longer.
Advantages of a fermented herb paste:
- extends the shelf life of fresh herbs
- intensifies flavors
- reduces food waste
- is versatile
- perfect for fermentation for beginners
Unlike classic pesto, the paste does not require oil as the main preservative. Instead, fermentation provides flavor and shelf life.
Fermentation can increase the bioavailability of certain vitamins, minerals, and phytochemicals because microorganisms break down cell structures and anti-nutrients and convert ingredients into more readily available forms. However, this effect varies in intensity depending on the plant and nutrient.
Recipe: Fermented Arugula-Basil Paste
Ingredients
- 350 g arugula
- 150 g basil
- 5 cloves garlic
- 20 g fresh ginger
- 2 small red chilies
- 13–14 g fine unrefined salt
––> Yields approx. 500 g paste
Also
Preparation
1. Wash herbs and dry completely
Wash arugula and basil thoroughly and then dry very well. This step is especially important because excess water can impair fermentation.
2. Chop and salt herbs
Roughly chop herbs or briefly process into a chunky paste. Peel garlic, wash ginger, and roughly chop chilies. Then mix evenly with salt in a bowl. The salt forms the basis of fermentation and helps to draw liquid from the herbs.
3. Fill into jar and compact
Portion the herb mixture into the jar and press each layer firmly down with a wooden tamper. This releases liquid, expels air, and the natural brine begins to form.
4. Let rest for 30 minutes
Close the jars with the fermentation lid and let them rest at room temperature for about 30 minutes. During this time, the salt will continue to draw water from the herbs, and the mixture will become noticeably juicier. After 30 minutes, you will notice:
- the paste appears moister
- it is easier to compress
- often, some liquid has already collected on the surface
5. Weigh down with a glass weight
Once enough brine has formed, weigh down the herb mixture with a glass weight. The herbs should remain as completely submerged under the liquid as possible.
6. Place fermentation lid and let ferment
Close the jar with a fermentation lid and let the herb paste ferment for about 3 days at room temperature. During this time, small bubbles may form, and the paste develops its typical spicy-sour aroma.
7. Taste and refrigerate
After 3 days, taste it. Once the desired acidity is reached, store the herb paste in the refrigerator.
Tools & Fermentation Must-haves
Serving Suggestion for your Herb Paste
Place the fermented herb paste in a small bowl and serve with:
- some good olive oil
- crumbled feta cheese
- toasted pine nuts
Especially good with:
- toasted sourdough bread
- warm bagel
Important: Refine only after fermentation
Olive oil or other fatty ingredients should only be added after fermentation. Before that, oils can destabilize fermentation and trap oxygen. Once the paste is fully fermented, you can refine it to taste.
Learning Fermentation Made Easy
If you're just starting out with fermentation, the right tools will help you better understand the process.
Our Fermentation Starter Sets & Tools will guide you step-by-step through the entire process – from compacting the herbs and using glass weights to safe fermentation with special fermentation lids.
This turns a simple recipe into an introduction to a technique that you can apply to new ingredients again and again.
FAQ: Fermenting Herbs
Can I substitute basil with other herbs?
Yes. The method also works with parsley, dill, cilantro, mint, or your own herb blends.
How long does a herb paste need to ferment?
For this recipe, we recommend about 3 days. The longer the fermentation, the more intense the aroma develops.
How long does fermented herb paste last?
Fermented herb paste usually lasts several weeks to months in the refrigerator. Always ensure clean work and hygienic removal.
Can I freeze fermented herb paste?
Yes. This will also make it last longer.
What are the most common mistakes when fermenting herbs?
Too little salt, not fully dried herbs, or herbs not kept sufficiently submerged under the brine are among the most common mistakes.
What to do if Kahm yeast forms?
Kahm yeast is usually harmless and can be carefully removed. It is important that the ferment continues to smell pleasant and shows no signs of spoilage.
You can find more information on the topic of mold in fermentation here.
How does fermented herb paste differ from classic pesto?
Pesto is usually preserved with oil and consumed directly. A fermented herb paste develops additional flavors through lactic acid fermentation and is naturally preserved.
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