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Food and the Colour Blue

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Blue fruit.

There is something of an aversion among human beings to food of a blue tinge: this is most likely due to the rarity of blue colours in edible plants and animals. Blue is often associated with alkaline conditions, whereas most organic life is mildly acidic. Food scientists have conceded that there are no natural food dyes of a blue colour1, and yet psychological research has concluded that blue is a relaxing colour with a positive influence on mental and physical performance. Nevertheless, there are a few brave foodstuffs that daringly cross the boundaries and promote themselves, bravely, as blue...

Blue Foodstuffs

Here you will find that which is eaten that has the strongest claim towards being naturally blue2.


The Vaccinium bush (from the Latin vacca = 'cow', because cows have something of a fondness for them) is the source of perhaps our best known blue food. The blueberry is high in iron and antioxidants, and is used most frequently in fruit puddings and muffins. With comparatively little rivalry, it is perhaps unsurprising that they have been chosen as the State Berry (no, really) of Maine, USA. They also go by the name of 'whortleberries' or 'hurtleberries'.

Bilberries are a close European relation of the North American blueberry, and the lesser known huckleberry also produces fruit of a blueish hue.

Another blue berry, although not a blueberry (note the subtle difference), is the sloe or blackthorn berry, which is used to flavour certain varieties of gin. The blackthorn bush grows wild in proliferation in the UK, and less so on northern mainland Europe. The berries are quite bitter when young, but this flavour is lost as they ripen - either on or off the bush.

Blue Corn

Blue corn kernels turn a very dark blue-black tinge as they are dried, and the flour produced from them is particularly used in making tortillas (some of which are fried or roasted into corn chips) and bread. It has been part of the staple diet of Hopi American Indians for hundreds of years, and has today acquired a reputation among organic farmers for its pleasantly pronounced taste, unencumbered by chemical fertiliser.

Borage Flowers

The leaves of the Borago officinalis plant have long been prized as a herb: often medicinal, but also for use in salads and bouquets garni. The flowers can also be eaten, having a slightly cucumber-like flavour which can be added to puddings or even infused in hot water to make borage tea. They are tipped by many to become the next 'in' food; outlandish recipes such as 'borage fritters' and 'borage and chickpea coulis' are already published.

Red Cabbage

Eh? Surely some mistake. Well, no actually. Red cabbage, like many vegetable products with a strong colour (particularly beetroot, geranium flowers and red onions) is an effective indicator of pH - chemical acidity. When it is cooked in alkaline conditions, it turns a rather unpleasant pale blue colour. That's why all red cabbage recipes include a quantity of vinegar or lemon juice: both are very acidic substances.

Bridget Jones's Soup

The film version of Bridget Jones's Diary has our culinary-disadvantaged heroine wishing to wrap a bunch of leeks in string to make soup. Unfortunately, the only string she has is of the blue plastic variety. This, of course, melts in the hot pan, and she winds up serving blue (and, no doubt, somewhat odd-tasting) soup to her dinner party guests.

Dentrassi Delicacies

Afficionados of BBC TV's adaptation of The Hitchhikers' Guide To The Galaxy will possibly recall that the famous Dentrassi 'Haggra biscuit' was a vivid royal blue in colour. Unfortunately, Arthur Dent appeared not to have the correct taste buds to savour its full appeal.

'Blue' Foodstuffs

No doubt wishing to cash in on the glories of blueberries, blue corn and the like, several foodstuffs have acquired the 'blue' moniker, but are not really of that shade at all. So, who are these imposters?

Blue Cheese

The distinctive veins in blue cheeses - the best known being stilton, gorgonzola and roquefort - were traditionally created by aerating the cheese to promote the growth of mould of the Penicillium genus. The aeration is done by inserting by steel or copper wires, which can either be left in place or removed during the maturation process. The cheeses were originally ripened in cool caves, where this particular mould was rife. In these days of mass production, the mould is artificially added during production. The result is a greenish-blue network of veins throughout the cheese, believed to heighten the taste through the oxidation or decomposition of certain flavouring compounds.

Countless regional variations on blue cheeses exist, particularly in France, and the products are considered best eaten alone as part of a cheeseboard or as a dressing for salads or steak. Like many fresh products today, European Union directives dictate that Stilton cheese may only be made in the Stilton region in Derbyshire.

Blue Kale

Kale, a cabbage-like breed of vegetable used in the Eastern Mediterranean for several thousand years, is frequently cultivated in cold climates as it is particularly tolerant of frost, and has been known to flourish in such chilly areas as Siberia and Northern Canada. Kale is a rich source of Vitamin A, and is useful in salads, as it does not wilt as quickly as other decorative leaves. Several varieties boast a 'blue' name, and grow with almost bluish-green leaves; you would probably not, however, see a definite blue colour by the time it arrived on your plate.

Blue Potatoes

The blue potato is actually a deep purple colour, originally caused by a virus infection. The 'Salad Blue' variety, commercially available today, has been carefully crossbred to remove all infection. As the name suggests, it is a small, floury variety of particular use in adding colour to salads or as a 'novelty' vegetable accompaniment.

Blue Steak

Steak cooked very rare, called 'blue'3 in resemblance of the blue veins which should still remain, is recommended for the best cuts of meat (certainly fillet, which sometimes lacks flavour, and often rib-eye too) and many rare-breed and well-hung cuts of beef. Although many shudder at the concept for being 'bloody', a good steak should shed very little blood, if any.

A particularly popular variety, especially in the USA, is 'black and blue steak'. This is marinated, usually in a soy-based dressing, and seared over a very, very high heat until the outside is blackened but the inside remains uncooked. This is classic 'texture' food - it is less about flavour than the contrasting textures of the crispy outside and the soft, squidgy middle.

Blue 'Foodstuffs'

There is an increasingly large sector of foods which are extremely blue coloured, but only vaguely fall within the heading of dietary necessities...

Blue Mints and Blue Toothpaste

The association between mint and the colour blue presumably arose through the flowers of the peppermint, which are a pale violet. It certainly did not arise through the most commonly used (and minty!) part of the plant - the leaves, which are dark green. Nevertheless, blue is commonly associated with mint sweets and chewing gum, and in a range of oral hygiene products.

Blue Smarties

Smarties, for those who don't know, are coloured, sugar-crisp coated discs of chocolate, made by the Rowntree company, recently swallowed by the Nestlé corporation. They are available in cardboard tubes and have been extremely popular since the 1940s for little more reason that the fact that a random lower-case letter is printed on the reverse of each tube lid. This presumably incites Smartie addicts to collect a full alphabet.

Smartie connoisseurs were long aware that certain colours of Smartie contained different sorts of chocolate - the orange one contains orange-flavour, for example. In 1989, the light brown Smartie, containing coffee-flavoured chocolate, was deemed unpopular and replaced by the blue Smartie. A large marketing campaign encouraged children to believe that blue Smarties were 'cool', and a widespread rumour sprang up that the blue colourings involved were dangerous to health (rumours of hyperactivity were most common). This was presumably based on the novelty of blue-coloured sweets and was entirely false. However, there is an interesting comparison with the next blue food...

Blue Ice-pops/Freeze-pops

The Ice-pop, a humble frozen lollipop in a thin, transparent polystyrene tube, has become a low-cost summer favourite, and unsurprisingly comes in a whole range of flavours. However, the raspberry flavour was to become more notorious than most:

It will be noted that many fruit flavours lend themselves to a red hue: strawberry being the most common, but raspberry and cherry following up closely. Obviously this presented a dilemma for junk-food manufacturers. If any two of these flavours were to be included in the same product, they needed to be distinguishable by colour. The colour arbitrarily adopted for raspberry flavours, for a short period at least, was a dark wine-red hue. Unfortunately, the most widely-available and cheap colouring for this selection was Amaranth (or E123). Not long after the launch of this colour in several brands of Ice-pop was Amaranth found to provoke severe allergic reactions, and was classified 'Very Dangerous' by the Food Standards Agency. So, a radical conclusion was reached: all raspberry ice-pops were coloured blue! This particular colour was favoured for no better reason than it was a spare colour in most companies' product range, and yet it surely started a small trend of popular blue food.

Blue Drinks

Without a doubt, the best known blue drink is Blue Bols, a Blue Curaçao variety flavoured with bitter orange peel, artificially coloured, and produced that hue simply for marketing purposes - how many other blue drinks are there on the market, after all?

Well, there are one or two. There are a couple of blue gin varieties available, the best-known being Bombay Sapphire, which are actually coloured by a tinted bottle, rather than an additive to the drink. A newer blue gin, Magellan, claims to be naturally coloured by use of iris extracts.

Sadly, in these days of 'novelty' drinks, one or two blue-coloured alcopops have also made it onto the market. The best known has a flavour vaguely reminiscent of bubble gum and should not be ordered by anyone who wishes to maintain any social status whatsoever.

There are also a handful of soft drinks, both carbonated and uncarbonated, on the market which bear an unnatural blue tint. Most of these follow the raspberry-flavouring theme made popular by Ice-pop companies, but such oddities as 'blue cola' and 'blue lemonade' have been known to make brief appearances, as well as a few varieties of glucose-rich 'energy' drinks.

The Blue Packaging Debate

Perhaps the biggest hoo-hah ever kicked up about the colour blue and food, this story doesn't actually involve any blue foodstuff whatsoever:

The first flavoured potato crisps4 were a cheese and onion flavour, developed by Smiths in 1962. Many companies followed suit, but for many years there were only cheese and onion or plain crisps to choose from. An unspoken agreement existed among the manufacturers that 'flavoured crisps' (remember, there was only one 'flavour') would be packaged in green bags to make them easier to distinguish on the shelves. Then Walkers got in on the act, a bit late considering they had been making potato crisps since the late 1940s. A far-sighted marketing man, now sadly anonymous, decided that Walkers cheese and onion should be served in blue bags, not the industry-standard green.

This, of course, paid off magnificently. Within a few years, there was a third flavour: salt and vinegar. Walkers made them in green bags, everyone else in blue. Naturally, the crisp-buying public trusted the green bags that were familiar to them, when the manufacturers were trying to promote their new 'blue' flavour. By dint of the fact that they had not yet used their green packaging, Walkers sold many more times salt and vinegar crisps than the rest of their competition put together, and have remained the UK market leader ever since. A true success for the colour blue!

1See a Chemical & Engineering News article on Food Colourings for a full explanation.2Many forms of shellfish are blue before cooking (including blue crabs), but as they change colour during the cooking process, perhaps our observations should concentrate on those products suitable for consumption.3Or, more properly, 'bleu' - the French equivalent.4Potato chips, if you're American.

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