|Nutritional value per 100 g (3.5 oz)|
|Energy||146 kJ (35 kcal)|
|- Sugars||0.49 g|
|- Dietary fiber||0.3 g|
|Vitamin A equiv.||260 μg (33%)|
|- beta-carotene||3121 μg (29%)|
|Thiamine (vit. B1)||0.098 mg (9%)|
|Riboflavin (vit. B2)||0.446 mg (37%)|
|Niacin (vit. B3)||1.47 mg (10%)|
|Pantothenic acid (B5)||0.521 mg (10%)|
|Vitamin B6||0.159 mg (12%)|
|Folate (vit. B9)||146 μg (37%)|
|Vitamin C||39 mg (47%)|
|Vitamin E||1 mg (7%)|
|Vitamin K||4 μg (4%)|
|Calcium||70 mg (7%)|
|Iron||1.8 mg (14%)|
|Manganese||0.988 mg (47%)|
|Phosphorus||58 mg (8%)|
|Potassium||356 mg (8%)|
|Sodium||48 mg (3%)|
|Zinc||1.05 mg (11%)|
|Link to USDA Database entry
Percentages are relative to
US recommendations for adults.
Source: USDA Nutrient Database
Laver is an edible, littoral alga (seaweed), and has a high content of dietary minerals, particularly iodine and iron. Laver is predominantly consumed in East Asia, where it is known as zicai in China, nori in Japan, and gim in Korea. In Wales, laver is used for making laverbread, a traditional Welsh dish. Laver as food is also commonly found around the west coast of Britain and east coast of Ireland along the Irish Sea, where it is known as slake.
It is smooth in texture and forms delicate, sheetlike thalli, often clinging to rocks. The principal variety is purple laver (Porphyra umbilicalis). Purple laver is classified as a red alga, tends to be a brownish colour, but boils down to a dark green pulp when prepared. It is unusual amongst seaweeds because the fronds are only one cell thick. The high iodine content gives the seaweed a distinctive flavour in common with olives and oysters.
Laver cultivation as food is thought to be very ancient, though the first mention was in Camden's Britannia in the early 17th century. It is plucked from the rocks and given a preliminary rinse in clear water. The collected laver is repeatedly washed to remove sand and boiled for hours until it becomes a stiff, green mush. In this state, the laver can be preserved for about a week. Typically during the 18th century, the mush was packed into a crock and sold as "potted laver".
Cultivation of laver is typically associated with Wales, and it is still gathered off the Pembrokeshire and Carmarthenshire coasts, although similar farming methods are used at the west coast of Scotland.
Laver can be eaten cold as a salad with lamb or mutton. A simple preparation is to heat the laver and to add butter and the juice of a lemon or Seville orange. Laver can be heated and served with boiled bacon. It is used to make the Welsh dish known as laverbread.
Laverbread (Welsh: bara lafwr or bara lawr) is a traditional Welsh delicacy made from laver. To make laverbread, the seaweed is boiled for several hours, then minced or pureed. The gelatinous paste that results can then be sold as it is, or rolled in oatmeal; it is generally coated with oatmeal prior to frying.
Laverbread is traditionally eaten fried with bacon and cockles for as part of a Welsh breakfast. It can also be used to make a sauce to accompany lamb, crab, monkfish, etc., and to make laver soup (Welsh: cawl lafwr). Richard Burton has been attributed as describing laverbread as "Welshman's caviar".
Laver is often associated with Penclawdd and its cockles, being used traditionally in the Welsh diet and is still eaten widely across Wales in the form of laverbread. In addition to Wales, laverbread is eaten across the Bristol Channel in North Devon, especially around the Exmoor coast around Lynmouth, Combe Martin and Ilfracombe. In North Devon it is generally not cooked with oatmeal and it is simply referred to as 'Laver' (lay-ver).
See also 
- Dilisk – another edible seaweed
- Edible seaweed
- Gim – similar style food in Korean cuisine
- Nori – a similar-tasting Porphyra common in Japanese cuisine
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- Wells, Emma (2010), A Field Guide to the British Seaweeds, National Marine Biological Analytical Quality Control Scheme (p 24).
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- Laver (Porphyra umbilicalis) at Wikimedia Commons
- Laver (Porphyra umbilicalis) at Wikispecies
- Laver (Porphyra umbilicalis) at Integrated Taxonomic Information System
- Laver (Porphyra umbilicalis) at Encyclopedia of Life
- Laver (Porphyra umbilicalis) at BioLib
- Laver (Porphyra umbilicalis) at Global Biodiversity Information Facility
- Laver (Porphyra umbilicalis) at Animal Diversity Web