Caviar is considered one of the most luxurious of foods, and its high price tag guarantees you won’t eat too much. That’s just as well if you have hypertension, as over-indulging in these salt-cured eggs could increase your blood pressure.
Types of caviar
Caviar is the salt-cure, unfertilised roe of the Sturgeon fish and was originally harvested from those swimming wild in the Caspian Sea, Black Sea and Amur River. As most sturgeon are endangered in the wild, almost all caviar is now produced from lovingly farmed fish, with production even occurring in a lake on Exmoor in the UK.
A female sturgeon, in her prime, is capable of producing up to 3 million eggs, weighing as much as 40kg in total.
Traditional roe harvesting involves killing the sturgeon, although the fish itself is also eaten. Newer techniques involve making a small surgical cut (C-section caviar) or even the ethical purging of ripe eggs by massaging them from the engorged female. These newer techniques allow the sturgeon to survive and spawn again 15 months later.
Of the 27 species of sturgeon, the main ones used for caviar production are the Russian, Siberian, Starry, and European sturgeon. The best caviar has a grainy texture, pops in your mouth, and has a buttery consistency that melts in your mouth to release a fresh taste of the ocean.
The starry or stellate sturgeon (Acipenser stellatu) produces Sevruga caviar, which consists of small eggs that are a dark-grey or light, pearlescent grey. Sevruga caviar has a more assertive taste than other varieties, and is often described as salty or briny. Sevruga caviar is relatively less expensive, and accounts for around half of all caviar production as Stellate sturgeon are common and reproduce at the relatively young age of around 7 years although the best Sevruga caviar comes from fish aged 18 to 22 years.
Siberian sturgeon (Acipenser baerii) produces caviar that is small to medium in size and a deep mahogany to black colour. Females are not mature enough to produce eggs until the age of 20 to 28 years in the wild, but when reared in fresh water lakes, it matures earlier. Its caviar has a stronger salty, briny taste than other caviars.
The Russian osetra (also spelled ossetra or oscietra) sturgeon (Acipenser gueldenstaedtii) produces medium-sized caviar with a nutty taste. It ranges in colour from deep brown-black to golden-yellow or even pale gold. The lighter-coloured eggs are the most sought after as they are produced by the oldest fish and have the richest flavour.
Caviar from the Beluga or European sturgeon (Huso huso) is the largest in size and also one of the most prized due to its creamy, smooth, buttery texture. Beluga sturgeon do not produce eggs until they are around 20 years of age, and Beluga caviar varies in colour from a pale silver or light blue to jet black. The sale of Beluga caviar that swim in the wild, such as in the Caspian Sea or Black Sea is banned in some countries to allow Beluga populations to recover in number.
The Kaluga or Mongolian sturgeon (Huso dauricus) from the Amur River, is the largest freshwater fish in the world, but spends part of its life in salt water. It is often referred to as the River Beluga. Hybrid varieties of caviar from Kaluga, cross-bred with Beluga, Siberian or Japanese sturgeon (Acipenser schrenckii), are increasingly available.
Imperial Caviar is a rare type of caviar from the almost extinct Sterlet sturgeon (Acipenser ruthenus). Rarest of all, and once reserved for royalty, is Golden Caviar, or Almas, which is almost white in colour, and produced from the even more rare albino Sterlet when they are 60 to 100 years old.
Some modern osetra-style caviar now comes from the Pacific white sturgeon (Acipenser transmontanus) or the American shovelnose or hackleback sturgeon (Scaphirhynchus platorynchus) and is sometimes referred to as American osetra.
Other non-sturgeon forms of ‘substitute’ caviar are also available, from fish such as capelin, steelhead, trout, lumpfish, whitefish, the burgundy-coloured caviar from carp, and the red caviar from salmon.
The salt in caviar
Caviar is preserved in salt to both enhance its natural flavour and lengthen its shelf life. Before the invention of refrigeration, more salt was used, so the caviar could be stored in wooden barrels, but too much salt compromises the taste and quality of the caviar. Excess salt causes the eggs to soften and lose their characteristic ‘pop’ on the roof of your mouth when you bite into them.
The finest caviar was therefore traditionally made with the lowest possible levels of added salt, and were labelled as ‘Malossol’ or ‘Mallasal’ – a Russian term meaning ‘low salt’. This type of caviar typically had a salt content of 3% to 5%.
With the availability of refrigeration, and modern vacuum techniques which remove air from the containers, less salt is needed. As a result, almost all modern caviar is classed as malossol, or low in salt.
Different manufacturers add different amounts of salt to their caviar blends, however. Typically, this varies from 1% (ie 1 gram salt per 100g caviar) up to 5% (5 grams salt per 100g caviar). Some traditionally salted caviars, and pressed caviar (which is made from overly ripe roe to produce a jam-like consistency and strong concentrated taste) can still contain up to 8% salt (8 grams sodium chlorine per 100g caviar). These highly-salted caviars are best avoided if you have high blood pressure as salt promotes fluid retention and can raise your blood pressure.
Before you buy caviar, especially in the most popular individual serving sizes of 1oz (28g), it’s important to check the ingredients list before you buy to check how much sodium is present (multiply by 4 to get the amount of sodium chloride salt). A caviar that provides 425mg sodium per 1oz (28g) serving, for example, will contain 425 x 4 = 1.7 grams of salt.
As a basic guide is that, per 100g food (or per serving if a serving is less than 100g):
0.5g sodium or more is a lot of sodium
0.1g sodium or less is a little sodium
Given that you should have less than 6 grams salt per day (and ideally no more than 3 grams) this is a significant amount. If you have high blood pressure, salted caviar can only be an occasional treat, or used as a garnish.
The Exmoor Caviar mentioned above is salted with Cornish Sea Salt and contains a relatively low-level of 3.2g per 100g – if you treat yourself to a 10g sized tin, this will provide just 0.32g salt, which is very doable.
Despite the added salt, caviar does provide other beneficial nutrients, including vitamin A, vitamin B12, vitamin D, choline, iron, potassium, selenium, calcium and magnesium as well as omega-3s. It is high in cholesterol, however, at around 440mg per 100g.
Pasteurised caviar may suit you better
Pasteurised caviar as made from fresh caviar that is vacuum-packed for longer preservation, and gently heat-treated (to a temperature of 60-65 degrees Centigrade) to preserve the original taste. This process requires less salt as a preservative and may be best if you have high blood pressure, although salt is still added for flavour.
How to eat caviar
Caviar is usually served on ice to preserve the flavour, but should not be frozen as this will cause the eggs to burst and destroy the taste. The caviar is spooned from its container using a caviar spoon fashioned from mother of pearl, bone or other non-metallic material as some metals – especially silver – can taint the flavour of the delicate roe.
Caviar was traditionally eaten from the ‘anatomical snuffbox’ – the web of skin between the index finger and the thumb.
The eggs are rolled around the mouth and ‘popped’ between the teeth or roof of the mouth to release the flavour.
Caviar may be served on its own, with crackers, toast, on a blini, spooned on cooked new potatoes. The finest caviar is not served with accompaniments, but lesser quality caviars are enhanced by sour cream, crème fraiche, cream cheese, minced onion, and chopped hard-boiled eggs. It is not considered correct to flavour caviar with herbs or spices – even black pepper.
Caviar is usually paired with vodka or Champagne but again, alcohol can increase blood pressure.
NB There is some swearing with several renditions of the ‘F’ word in the following clip, which isn’t too surprising as it features chef Gordon Ramsay. It provides a fascinating look at caviar production and includes a recipe for lobster and caviar salad with new potatoes. Delicious as a special treat.
Image credits: Pixabay