Dulse (dried, raw?, organic?)

What is Atlantic dulse? Dulse, actually dulse ( Palmaria palmata ), is an edible seaweed from the subkingdom of red algae . For centuries, the dried macroalgae has been a traditional food in parts of Northern Europe and North America.

Use in the kitchen

Dulse has a subtle fishy taste as well as a nutty, spicy and slightly salty note. However, dulse is vegan. In dried form, the red algae has a crunchy but tender texture. Cooking or soaking the dried algae before further use or consumption is not absolutely necessary, but is required for some recipes.

Today, Atlantic kelp (organic?) ends up on plates mainly in Ireland, Iceland and Canada, often in chowders (fish soups) and fish dishes.

Dulse can be prepared in a similar way to leafy vegetables and can be used in many different ways due to its properties as a natural flavor enhancer. Seaweed enriches salads, soups, rice dishes, pasta, vegetables, smoothies and potatoes or is used as an ingredient in hearty bread. Soaked beforehand and then fried in a pan until crispy, dulse makes a tasty side dish, also known as "bacon from the sea." Dried dulse is a popular snack and goes well in desserts as well as nut or dried fruit mixes. Powdered or flaked dulse serves as a mild seasoning and salt substitute.

Dulse is a popular ingredient in raw food cuisine, e.g. as a topping for salads or vegetable noodles.

Depending on the intended use, dried dulse (kelp) is soaked for about five minutes beforehand. This increases the weight and volume by about six times. Dulse flakes can be left to steep in water in a fine sieve.

Caution: Since dried dulse contains a lot of iodine, a daily portion of 2-4 g is usually the recommended maximum. You can find out more about the health risks of eating seaweed in the "Danger - Intolerances - Side Effects" section below. To be on the safe side, use dulse sparingly like a spice. Repeated soaking and pouring away of the water reduces the iodine content.

Homemade preparation

Fresh dulse is dried in direct sunlight immediately after harvesting to make hard crackers. This way, the quality of the edible seaweed can be largely retained.

Vegan recipe for wild rice salad with dulse (kelp)

Ingredients (for four people): 70 g wild rice ; 8 g dulse, dried and soaked for approx. 10 minutes; 3 spring onions ; 200 g tofu, natural ; 2 tbsp sesame seeds ; 15 g ginger ; 2 tbsp rice vinegar ; ½ tbsp tamari soy sauce ; 2 tbsp agave syrup ; ½ tsp sesame oil, roasted .

Preparation: Cook the wild rice in three times the amount of water for about 40-45 minutes. Then let the cooked rice cool down. Cut the spring onions lengthways into thin strips and put them in ice-cold water. Cut the tofu into bite-sized pieces. For the dressing, finely chop the peeled ginger and add it to the vinegar, tamari, agave syrup and sesame oil.

Place the drained seaweed and the strained spring onions in a large bowl. Mix all the ingredients together with the cooked rice, tofu and dressing. Finally, sprinkle sesame seeds over the finished salad. You can find the full recipe description HERE .

Vegan recipes with dried dulse can be found under the note: " Recipes that have the most of this ingredient ".

Purchasing - Storage

Dried dulse can be bought in delicatessens, online or in organic shops all year round in different qualities. There is organic dulse seaweed, organic dulse flakes and organic Atlantic kelp. The price can range from just under €10 to well over €30 per 100 g.

What is dulse powder? What are dulse flakes? In addition to dried dulse leaves, flakes and powder are available on the market. About 10 g of dried dulse can be obtained from 100 g of fresh algae. Its effect ("dulse flakes effect" or "dulse powder effect") is basically the same as that of dried dulse algae.

We have not yet found any dulse products in supermarket chains such as Migros, Denner, Volg, Spar, Aldi, Lidl, Rewe, Edeka or Hofer, or in the organic supermarkets Denns and Alnatura . In larger Coop branches, you can find kelp under the name 'Algues de Bretagne Dulse'.

Labels such as raw food (raw quality), air-dried, wild-harvested, sustainable hand-harvested, residue-controlled or certified sustainable production can indicate particularly gentle extraction and high quality of the product. Choose organic quality, because algae can absorb heavy metals from polluted water. See also "Ecological aspects" below.

The red algae species Dulse is only available fresh in specific regions. In Germany, raw Dulse from France is in season from May to October. You can buy it from fishmongers or specialist retailers, usually to order.

When buying algae, you should always choose products with a stated iodine content. However, these are average values, as the iodine content of algae is not standardized and therefore fluctuates greatly.

The availability of dulse (kelp) varies depending on the size of the store, catchment area, etc. You can find our recorded food prices for the DA-CH countries above under the ingredient image - and by clicking you can see their development at various suppliers.

Finding Wild

Dulse grows in the intertidal zone on rocky substrates and is native to coastal regions of the Northern Hemisphere. The season for harvesting wild dulse is in summer and fall . At low tide, the young seaweed is cut off by hand above the base and then rinsed thoroughly.

The diversely shaped kelp with its brown to purple-red coloring reaches heights of five to 50 centimeters. The shoot emerges from a disc-shaped base and expands into a lobe with a leather-like texture. These leaf-like branches with their finger-like extensions are very characteristic. They take on a wide variety of shapes and are eight to 30 centimeters wide. Most plants have small shoots at the base. Young plants can be less leathery, but thin and smooth. ^1,2

Wrack, which grows in exposed coastal areas, is considered very tasty and is known in Ireland as creathnach. The leathery and less tasty seaweed from semi-exposed shores is called dillisk or dilsk. A very fine form grows on rocks and the stems of saw kelp ( Fucus serratus ) in the sheltered areas of semi-exposed shores. This very rare variation is known as "var. sobolifera " or "var. sarniensis ". ²

Storage tips

Dried dulse should be stored in an airtight, cool, dry and dark place in a well-sealable glass container. When packed like this, dulse will last for months. If the algae absorb moisture, they can be gently dried again in the oven at 42 °C.

Fresh dulse has a short shelf life. It should be used quickly and stored in the refrigerator for only a few days. Cooked dulse can be preserved by freezing.

Ingredients - Nutritional value - Calories

Dried dulse is low in fat and consists mainly of carbohydrates, fiber and proteins. The red algae contains large amounts of unusual carbohydrates, including the small molecular floridoside, which can make up to 30% of the dry weight. Floridoside is probably responsible for the algae's palatability. Dulse is rich in minerals, trace elements and vitamins. Folate, manganese, potassium, vitamin C, copper and niacin are particularly noteworthy. The iodine content is extremely high at 7500 µg/100g. ²

According to the Austrian nutritional table ( ÖNWT ), dried red algae (type or variety is not further specified) contains 317 µg iodine per 100 g. ⁵ However, this value is more likely to indicate spirulina (461 µg/100g) or raw goods. The Federal Institute for Risk Assessment ( BfR ) gives an iodine content of 1,500-5,500 µg/100g for dried dulse ( Palmaria palmata ), ⁶ the United States Department of Agriculture ( USDA ) 7,500 µg/100g ³ and other sources up to 10,000 µg/100g.

Although dulse is rich in nutrients, due to the low recommended consumption amount, it cannot significantly contribute to the coverage of essential nutrients - with the exception of iodine. It is therefore important to ensure an adequate supply of nutrients through a varied and minimally processed selection of foods.

Which seaweeds contain a lot of iodine? The edible seaweeds that are particularly rich in iodine include bladderwrack (300,000 µg/100g), laminaria (kelp, seaweed forests) ( 300,000 µg/100g), kombu seaweed (200,000 µg/100g) and arame seaweed ( 70,000 µg/100g). Wakame (4200 µg/100g) and nori (3215 µg/100g) contain slightly less iodine than the dried red seaweed species dulse (7500 µg/100g). ³ The natural iodine content of seaweed can vary greatly, however.

You can find the complete ingredients of Dulse, the coverage of the daily requirement and comparison values with other ingredients in our nutrient tables. In the article Nutrients explained you will get a detailed insight into the topic.

Health effects

Are dried seaweeds healthy? Study results show the antioxidant potential of the peptides derived from Palmaria palmata . The use as a health-promoting ingredient in food is under discussion, e.g. also for the prevention and treatment of type 2 diabetes. ^7,8 Dulse kelp ( Palmaria palmata ) produces xylans (polysaccharides) as cell wall material, instead of sulfated galactans, as in most red algae. Studies show that xylans extracted from dulse are good raw materials for the production of bioactive xylo-oligosaccharides, which show positive health effects, such as lowering blood sugar levels and antioxidant effects. Water-soluble extracts containing xylans as the main substance show strong antiviral and anti-inflammatory effects in the treatment of herpes virus infections. ^9,22

Floridoside is a special sugar derivative found in seaweed and has an immunomodulating effect. It is used in the cosmetics industry as a patented melanogenesis inhibitor. Isofloridoside exhibits antioxidant activity and inhibits tumor angiogenesis in certain cell lines. ²²

The question of whether dulse is healthy cannot simply be answered with a 'yes', because with food it always depends on the quantity. The body can tolerate a lot, but with iodine and selenium the range is small.

Secondary plant substances

Many of the health effects of dulse (kelp) can be attributed to the secondary plant substances it contains. Our article on secondary plant substances provides an overview of the classification of substance groups, their occurrence in foods and possible effects on humans. Dulse (kelp) contains the following secondary plant substances, among others: ^22,23

• Isoprenoids: Triterpenes: Steroids (cholesterol, desmosterol, cholesta-4,6-dien-3-ol, cholest-5-ene-3,7-diol); Tetraterpenes: carotenoids (carotenes: alpha-carotene, beta-carotene; xanthophylls: antheraxanthin, cryptoxanthin, lutein, violaxanthin)
• Polyphenols: Phenolic acids: hydroxybenzoic acids (gallic acid, protocatechuic acid, genistic acid); flavonoids: flavanols (catechin), flavonols (quercetin, rutin), phlorotannins
• Other nitrogen-containing compounds: Mycosporin-like amino acids (cyclohexenone, cyclohexenime derivatives)
• Protease inhibitors: Chlorophyll A, Chlorophyll B

However, it should be noted that the composition of the secondary plant substances in dulse (kelp) can vary depending on the variety, time of harvest and growing conditions. Therefore, quantities are only of limited use and should only be understood roughly.

Phytosteroids extracted from algae are used in pharmaceutical production and food supplements. Cholesterol is present in very small quantities in red algae, except in purple kelp ( Porphyra ssp.), where it accounts for 8.6% of the total steroids. The steroids present have antioxidant, antiviral, antifungal and antibacterial effects. ²³

Carotenoids have antioxidant, anti-inflammatory, anti-tumor properties and reduce the risk of eye diseases in humans. Carotenoids from algae are found in everyday products as food coloring and as a component of cosmetics and medicines. The total carotenoid content in dulse is 800 mg/110g dry weight, including 24 mg/100g lutein, 8 mg/100g alpha-carotene, and 3 mg/100g beta-carotene. According to a study, dulse does not contain zeaxanthin, which is a common xanthophyll in other Rhodophyta. Polyphenols have a variety of bioactive properties such as antidiabetic, antioxidant and anticarcinogenic effects. ^22,23

The mycosporin-like amino acids produced by Rhodophyta algae also have a photoprotective effect and help protect against UV rays. The water-soluble, nitrogen-containing mycosporin-like amino acids absorb UV light particularly well and also have antioxidant, immunomodulatory and anti-inflammatory effects. ^22,23

Read more about the health effects of the secondary plant substances in red algae .

Dangers - Intolerances - Side effects

As seaweed is naturally rich in iodine, excessive intake can lead to thyroid dysfunction and sometimes serious health problems. Dried seaweed and kelp generally contain between 500 (spirulina, actually a cyanobacterium) and 330,000 µg/100g. The BfR therefore recommends setting uniform maximum levels in the European Union ( EU ). Manufacturers and suppliers of seaweed products should also be required to provide mandatory information on the effects of seaweed. The BfR considers dried seaweed products with an iodine content of 20 mg per kilogram (2000 µg/100g) and higher to be unmarketable for reasons of preventive health protection. ¹⁰

Basically, the recommended iodine intake depends on whether it is an iodine-deficient country like Germany or an area where the population is adequately supplied with iodine, e.g. the USA or Asia. In Germany, a maximum daily iodine intake of 500 µg is considered safe, even for people who are sensitive to iodine exposure. A "normal" diet does not exceed this value. ¹⁰

The German Nutrition Society ( DGE ) recommends an intake of 200 µg iodine per day for an adult. ¹¹ In addition, you should not consume more than 200 µg iodine per day through algae products so that you do not exceed the total iodine intake of 500 µg/day. An upper limit of 100 µg per day is recommended for food supplements. ⁶

Do not confuse µg with mg, a thousand times the amount! In practice, this means that you can eat two to four grams of dried dulse per day. A correspondingly higher intake may be possible if you add dulse less often and do not eat other strong sources of iodine. Make sure that you do not consume more than twice the amount of iodine over a longer period of time.

Shellfish between the leaves of the dulse can be an indirect allergen exposure. Make sure the red algae are cleaned thoroughly.

Kainic acid is a marine biotoxin that occurs in dulse and is similar in chemical structure to domoic acid, which acts as an amnesia-inducing algae toxin. Kainic acid is also thought to have a neurotoxic effect. However, due to large gaps in data on toxicity and exposure levels, the BfR has not yet been able to make a health assessment. ¹² According to the German Federal Aquaculture Association, there are no known cases of death or illness after consuming kelp. ¹³

Ecological footprint - animal welfare

Algae are more productive than land plants. Because they do not need cellulose as a supporting tissue, their nutrient density is often even better than that of terrestrial plants. ¹⁸ Seaweed cultivation can therefore produce large quantities of nutrient-rich food for human consumption. In addition, marine farming appears to be more sustainable than agriculture on land, as no fresh water ( water footprint ), no chemical fertilizers and no land are needed to cultivate seaweed; these are major negative factors of agriculture. ¹⁷

One issue related to future sustainable food sovereignty is ensuring adequate nutrient supplies. Animal protein is a good source of protein, but it has a very high _carbon footprint . Therefore, we need to look for alternatives. Red algae could be ^such a sustainable protein source. Red algae have a comparable essential amino acid profile to ovalbumin (a very valuable protein found in large quantities in eggs) and represent a sustainable alternative to terrestrial proteins.16 To illustrate, beef has 13.6 kg _CO2 eq/kg, eggs 3 kg _CO2 eq/kg and organic lentils 1.7 kg _CO2 eq/ ^kg.19 While fresh seaweed has -7.21 kg _CO2 eq/ ^kg20 to 0.0575 kg _CO2 eq/kg. ²¹ However, the further processing of seaweed and the actual management of aquaculture can also significantly increase the greenhouse potential – dried sugar kelp has an emission level of around 6.12 kg CO ₂ eq/kg. ⁴

In addition, organic marine products are recommended, as is the case with land products, in order to protect nature and us too: The EU stipulates criteria for the controlled organic wild collection (wild harvest) of algae. The harvest of the algae that will later be certified organic must not take place near busy ports, nuclear power plants, sewage discharges, conventional aqua farms or other sources of pollution. In addition, the collection must be sustainable so that stocks are preserved and inhabitants living in the sea remain unharmed. ¹⁴

For detailed explanations of various sustainability indicators (such as ecological footprint, _CO2 footprint, water footprint), see our article: What does the ecological footprint mean?

Worldwide occurrence - cultivation

Where does parsley come from? Cultivation areas? Genetic center? According to Wikipedia, the oldest tradition of using kelp as a food ingredient can be found in the 6th century by Columban of Iona . The book Edible also refers to Ireland and the 6th century. ¹ The Icelandic sagas mention the type of seaweed from the 11th century onwards and in the 13th century regulations were introduced for collecting dulse. ²

This perennial red algae is distributed in the arctic-cold temperate coastal regions of the northern hemisphere. In the Atlantic Ocean it is the only species of the genus Palmaria . The Atlantic dulse algae can tolerate ice-cold sea water of -1 °C and dies at 22 °C. ¹³

Dulse is common in the intertidal zone of the Atlantic and Pacific and sometimes forms populations. Dulse grows on stones, mussels, rocks, epiphytes or other algae, e.g. in the upper part of the stalks of palm kelp ( Laminaria hyperborea ). ²

Dulse is found from northern Portugal to the Baltic States and Iceland, as well as on the coasts of Russia, Arctic Canada, Alaska, Japan and Korea. On the Californian coast, Palmaria mollis is found instead of Palmaria palmata . ¹

Cultivation - Harvest

Scotland, Norway, Iceland and Eastern Canada produce small quantities of dulse for human consumption. Ireland sells about 20 tonnes of dry matter of dulse annually. Dulse is currently in short supply. ²

Since the cultivation of dulse is very difficult and demanding, wild algae are often harvested for commercial use. In Ireland, dulse was also cultivated on ropes in the sea. Wild plants from nature were used for this or the seedlings were grown from the spores. In Germany, dulse was produced for cosmetic purposes in tank cultures. Sea rope cultures are not possible in the German coastal area - in the Baltic Sea because of the low salt content and in the North Sea because of the Wadden Sea National Park. ¹³

The related and also edible red algae species Gracilaria multipartia looks similar. However, the finely divided forms of the kelp differ from the much thicker and noticeably fleshy texture of Gracilaria multipartia .

Further information

Dulse ( Palmaria palmata ) is a perennial and edible macroalgae from the subkingdom of red algae (Rhodophyta, less frequently Rhodoplantae). Wikipedia underlines that Dulse is the only species of the genus Palmaria that occurs in the Atlantic Ocean.

Alternative names

In German, Palmaria palmata is known as dulse, palm leaf red algae or palm leaf seaweed.

In France it is known as dulse or algue dulse (petit goémon, goémon à vache, algue à vache, not "dulce") and in Iceland as söl.

In Great Britain and Ireland this red seaweed is called dulse, creathnach, dillisk, dilsk or dilleasc.

Other applications

Wrack is suitable for bioremediation: for the biological rehabilitation of the sea. ⁶