What is Kombu Seaweed?
Kombu is simply the Japanese word for dried sea kelp.
Kombu/Kelp/Haidai, are large seaweeds (algae) belonging to the brown algae (Phaeophyceae) in the order Laminariales. There are about 30 different genera* around the world (see Laminariales for more information). Various species of kelp grow around the world, according to climate, current and conditions. Kelp seaweeds grow in underwater “forests” in shallow oceans. They require nutrient-rich water with temperatures between 6 and 14 °C (43 and 57 °F) and are known for their rapid growth rate.
In New Zealand, we have several different species of kelp, the better known are Bull Kelp (Durvillia), Macrocytis kelp (or South Island Kelp) and Ecklonia Kelp (or North Island kelp). Pacific Harvest only works with Ecklonia radiata, sustainably wild harvested from the North Island of New Zealand – we think it tastes the best of all the options!
Kelp is highly valued for its abundance of essential minerals, vitamins, and trace elements, as well as its natural glutamic salts: a naturally sweet, superior flavor enhancer which creates the famous savory “fifth taste”, also known as ‘Umami‘ in Japanese cuisine.
So to answer, “what is kombu”, it’s essentially just a dried piece of kelp seaweed! Kombu is known for the important role it plays in Japanese cuisine and is also eaten in other parts of Asia. The exact type of kelp made into kombu (naturally dried) will vary according to location. In Japan, for instance, the ‘Saccharina japonica’ kelp is the most prolific. All of the parts of the kelp plant are used, including the thick stalks and fronds (leaves in seaweed vocabulary).
What is a kombu strip vs. kombu leaf?
Kombu strips are tough and can be a bit spikey to touch – they are from the stem or ‘trunk’ of the kelp. These are excellent to pop into water to make broth or stock.
The kombu leaf is technically the blade or frond (leaf) of the kelp plant. It is softer and more malleable than the strip and has a gentler flavour. It is also excellent for use in making broths and soups but can also be used to wrap around fish, infusing a delicious flavour and boost of minerals to your meal.
What is Kombu’s Role in Providing Stunning Umami Flavour?
You may notice a fine, fluffy white powder on Kombu strips and leaves. This is not, as you may first assume, mould! It is in fact an amino acid called glutamine which naturally rises to the surface of the seaweed as it dries. This is also the source of wonderful umami flavour kombu can impart in meals.
The white powder, ‘Glutamine’ is one of the 20 amino acids encoded by the standard genetic code. It is not recognized as an essential amino acid but may become important in certain situations, like intensive athletic training or certain gastrointestinal disorders. It is also said to be a superb brain fuel, and some people refer to it as a “smart-vitamin” – although it is in actual fact not a vitamin at all. Read more about umami in our blog article.
When air dried naturally, this thin layer of white powder emerges from the leaf, which is full of flavour. When preparing kombu, this powder should not be washed away, but if there is any foreign material the strip can simply be wiped clean with a slightly dampened cloth.
Kombu left exposed to air will become damp (like sea salt, the high quality minerals attract moisture) and its flavour will be reduced. We recommend keeping all seaweeds in an air tight container once opened. Damp kombu can be dried again under the sun or in a very low temperature oven (47 C or lower). Note, when you heat seaweed the nutrient density can be impacted – we only air dry our kombu.
Making Kombu Strips and Leaves
Many different types of kelp can be used to make Kombu, and its preparation is very simple. In Japan, the whole seaweed is washed thoroughly with seawater, cut into 1 m lengths, folded and dried. The same process is used in New Zealand to prepare Pacific Harvest’s Kombu.
Cooking with Kombu
Kombu/kelp is one of the three main ingredients needed to make dashi, a soup stock used in a multitude of Japanese dishes. Making dashi is simple: a strip of dried kombu (or a tea strainer filled with kelp seasoning) is placed in cold water , then heated to near-boiling; then the flakes of dried smoked bonito, a type of tuna, are added. The softened kombu is sometimes eaten after cooking in Asian cusine.
Add a small piece of kombuor kelp seasoning added to dried beans helps to tenderize them as they cook, or just add to your stock ingredients or soup when you are making soups and stews in the same way you may add a bay leaf. This imparts a wonderful depth and umami flavour to your food and infuses additional nutrients and essential minerals and vitamins into your food.
Kombu and Weight Loss
In 2010 a group of researchers at the University of Newcastle found that a fibrous material in sea kelp (called alginate) was better at preventing fat absorption than most over-the-counter slimming treatments in laboratory trials. As a food additive it may be used to reduce fat absorption and thus obesity. Kombu/kelp contains very little calories and is a popular diet food. It contains the most potassium of all the sea vegetables. Kelp contains fucoidan, a type of polysaccharide known to activate the liver cells. It is said to also be effective in cleaning the blood and decreasing cholesterol levels.
* Genera is a phyto-taxonomy (plant nomenclature & classification) term for ‘families’ which contain many ‘genus’ which themselves have many varieties. As an example, Pacific Harvest’s kelp is Ecklonia radiata: Class= Brown seaweed or Phaeophyceae, Order= Laminariales (kelps), Genera/Family= Alariaceae, Genus= Ecklonia and Specie= radiata.
Disclaimer: The information contained in this blog article is intended to inspire and inform. It has been gathered after years of working with this amazing seaweed. It is not a replacement for personalised medical advice. Please consult a healthcare practitioner if you require tailored health advice.