Asparagus is a perennial plant that is native to the eastern Mediterranean and Asia Minor areas. The name “asparagus” comes from the Greek language meaning “sprout” or “shoot” and it is a member of the lily family as are onions, garlic, leeks, turnips and gladioli. The ancient Greeks loved wild asparagus but it was the Romans who first cultivated it.
Widely cultivated for its tender, succulent, edible shoots, asparagus cultivation began more than 2,000 years ago in the eastern Mediterranean region. Greeks and Romans prized asparagus for its unique flavour, texture and alleged medicinal qualities. They ate it fresh when in season and dried the vegetable for use in winter.
In the 16th Century, asparagus gained popularity in France and England. From there, the early colonists brought it to America. Asparagus is often called the “Food of Kings.” King Louis XIV of France was so fond of this delicacy that he ordered special greenhouses built so he could enjoy asparagus all year-round.
The Emperor Augustus coined the phrase ‘velocius quam asparagi conquantur’, meaning to do something faster than you can cook asparagus. Julius Caesar first ate it in Lombardy and wanted it served with melted butter.
The asparagus growing beds in Northern Italy were famous during the Renaissance period. These graceful spears of the asparagus plant have always been a sign of elegance and in the past asparagus was deemed a delicacy only the wealthy could afford. Roman emperors were so fond of asparagus, that they kept a special asparagus fleet for the purpose of fetching it.
Today asparagus remains loved for its versatility, unique herbaceous flavour, distinctive shape and health giving properties and food lovers around the world – from Europe (where white asparagus is ‘king’) to North America, Asia and Australia – feast on asparagus when in season.
Types of Asparagus
Green asparagus derives its colour from the process of photosynthesis as the spear emerges from the soil into direct sunlight. A common misconception is that thin spears are young shoots and therefore more tender. In fact, long, thick dark green glossy spears with tightly closed heads are the best quality. Correct cooking results in vibrant green spears with a delightful tender crisp texture. Green asparagus is usually available from the Koo Wee Rup area of Victoria from early September until the end of March.
White asparagus has long been considered a delicacy, particularly by Europeans, and commands about double the price of green asparagus. White asparagus is exactly the same variety as green asparagus grown in Australia. The difference is that white asparagus is grown in the dark. When asparagus spears are exposed to sunlight, they first turn pink and later, the familiar green colour.
The main reason that white asparagus is more expensive is that there is a limited supply, and the production costs are high. Traditionally white asparagus was produced in the field by hilling up extra soil above the crown so that the spear could develop to a harvest-able length without being exposed to sunlight. As soon as the spear emerged from the mound, specialist and skilled workers would cut deep into the mound with their purpose built long handled asparagus to harvest it. This method was not without its problems, as “blind harvesting” increased the risk of injuring the developing spears, and few specialist cutters were available to harvest the crop.
The increasing demand for new types of asparagus has led to developments in the way that white asparagus is produced. Some growers now use black “polyhouses” or “igloos” constructed over the crop between June and July in preparation for the emerging crop. The black plastic ensures that the spears are not exposed to sunlight. It also solves the problem of the traditional harvesting methods as asparagus grown in “polyhouses” can be harvested above the ground cleanly and efficiently without damaging the developing spears.
At the end of the season, the “polyhouses” are removed to allow the crop to continue its life cycle and produce the normal asparagus fern. White asparagus is usually available from September to January.
Purple asparagus is a different variety to green and white asparagus. Its purple colour comes from the high levels of anthocyanins (potent antioxidants) in the spears. It has a lower fibre content than white or green asparagus, making it more tender and the whole spear can be eaten from tip to butt. Purple asparagus produces sweeter, thicker spears than green or white asparagus. Fresh purple asparagus is deeply fruit flavoured and tender crisp. It is usually available in Australia October and mid December but currently only in limited supplies.
Asparagus Facts & Myths
- Asparagus cures cancer. False.
You may see an email suggesting that asparagus cures cancer. It says it comes from an article written by Richard R Vensal, published in the Cancer News Journal. No one has been able to find a copy of the journal article or the whereabouts of Mr. Vensal. We have to assume this is one of the many internet hoaxes that turn up in your email. Vegetables, like asparagus, certainly reduce the risk of getting cancer, but sadly, there is no evidence of a single vegetable curing cancer.
- Asparagus makes your pee smell funny. True (for some people).
To make the asparagus plant less attractive to parasites it produces a compound called asparagusic acid. This same compound, when eaten, is metabolised to other compounds that provide the characteristic bouquet of pee after we eat asparagus. Some people claim they notice the odour of their pee changes to one reminding them of cabbage, vegetable soup or, as you would expect, asparagus.It is still not clear which of the 29 proposed compounds give urine its asparagus smell. Some people don’t produce enough of the odorous compounds to be smelled in urine. Some people don’t have the ability to smell the compounds in urine even when they are present in sufficient amount.Although we all excrete the same compounds after eating asparagus, only around one in two people from a Caucasian background, and nine out of ten from a Chinese background can smell it. Whether our pee changes in odour after eating asparagus is all academic really because asparagusic acid and its metabolites are harmless.
- Asparagus is a diuretic. False.
Although some early research 70 years ago suggested asparagus is a diuretic, more recent research does not confirm that asparagus can stimulate excess urine production, nor can it specifically lower high blood pressure. However, as fresh asparagus is high in potassium and low in sodium (salt), like all vegetables and fruit, it will help maintain a healthy blood pressure.
- Asparagus is a good source of folate. True.
A serve of fresh asparagus can provide over 20% of our needs for this valuable vitamin. Expectant Mums need adequate folate for healthy babies, while everybody’s heart and arteries seem to be thankful for plenty of folate in the diet.
- Asparagus is a cause of gout. False.
Foods that are high in purines may cause a flare-up of a gout attack. Asparagus is not high in purines and, nowadays, very few physicians would recommend eliminating any vegetable from the diet of someone with gout.After reviewing all the evidence about food and gout Dr Choi, Professor of Medicine, Boston, USA recommended the consumption of vegetables, including those with purine, because people who ate the most vegetables had a 27% reduction in their risk of gout compared to those eating the least amount of vegetables. A recent study also found no association between purine-rich vegetables and blood uric acid levels.Gout tends to greatly improve with weight control, exercise and avoidance alcohol and, possibly, very high purine foods like offal and some seafood. Often medication is used to alleviate the painful symptoms of gout in joints. There is no reason to avoid or limit asparagus in our diet.
Fresh Australian asparagus is available from September to March, making it the perfect spring and summer vegetable for all menus.
No other vegetable signifies the arrival of spring like asparagus. The spring sunshine provides the warmth and the spring rains provide the moisture needed to encourage the emergence of the shoots (spears) from the crown of the plant lying beneath the soil.
Chefs and home cooks alike become excited when it appears in early spring, as this not only signifies that the weather is warming up nicely but that there is much delicious eating to be had!
Asparagus thrives in warm conditions with sufficient rainfall. The season can be delayed or slowed due to cold snaps, however as a guide:
- Green asparagus is available from early September to March.
- White asparagus is available from September to January.
- Purple asparagus is available from October and mid December but only in limited supplies.
Selecting & Storing Asparagus
Look for firm, bright smooth, spears of uniform size with closed, compact tips. When you snap freshly harvested asparagus, it should be crisp, moist and juicy.
Freshly harvested asparagus is very similar to cut flowers – it needs to be kept in cool, humid conditions. Below are two tried and true methods of storing fresh asparagus. Choose the method that suits you.
- To keep asparagus fresher for longer, wrap it in a damp tea towel, pop in a plastic bag and store in the crisper compartment of your fridge.
- Stand the fresh spears upright in a container with 1cm cold water, cover and store it in the refrigerator.
- Wash the asparagus thoroughly and remove the woody ends.
- Bring a large pot of water to the boil.
- Carefully add the asparagus. If you are blanching a large amount of asparagus, blanch in batches of 2 bunches to maintain the temperature of the water.
- Stand the asparagus in the boiling water for 1-2 minutes then remove immediately.
- Transfer the asparagus to a large bowl of cold water with ice cubes to reduce the temperature quickly and prevent further cooking.
- Drain the asparagus well on clean tea towels or paper towel.
- Transfer to freezer bags, secure and label with date.
- Store in the freezer until required for up to 8 months.
- Wash 2 kg asparagus and remove the woody ends.
- Cut the spears into 2-3 pieces.
- Place the asparagus in a large saucepan and cover with about 1.5 L of water and 1.5 L vinegar.
- Bring to the boil, stirring occasionally then remove the asparagus from the pan and drain well.
- Spread the asparagus out on clean tea towels or a tablecloth and allow to cool.
- Half fill clean empty sterilised jars with vegetable oil or olive oil and place the asparagus into the jars. If you like you can add your choice of flavouring – garlic, mint or chilli. Top up with oil to fill the jar and place on sealed lids.
- This asparagus is best eaten at least 8 days after bottling.
Preparing & Cooking Asparagus
Preparing and Cooking Green Asparagus
Most green asparagus is ready-to-go. Simply snap off the coarse ends with your forefinger and thumb. Alternatively, run a knife along the stalk until it meets less resistance, then cut the end off at this point.
Preparing and Cooking White Asparagus
White asparagus spears are usually thicker than green asparagus. White asparagus also has a thicker outer layer that can be easily removed. Simply use a vegetable peeler to carefully remove the outer layer of each spear two-thirds the length of the spear towards the tip, then snap or trim off any woody end.
Preparing and Cooking Purple Asparagus
Purple asparagus spears are between 10% and 15% wider at the base than green asparagus spears. To select the freshest spears, consumers should look for firm, crisp stalks and compact brightly coloured heads with no trace of softness.
When purple asparagus spears are sliced, the cream coloured flesh provides an especially effective presentation for salads and stir-fries. Cooking causes purple asparagus to turn a deep green / bronze colour. To retain the vibrant purple colour and tender crisp texture that makes purple asparagus so special, it is best to serve it raw in salads and salsas or add it to a dish at the end of cooking. Or serve it fresh in salads and salsas. Interestingly, adding ‘acidic’ dressings using lime or lemon juice, white wine vinegar or apple cider vinegar can help intensify the beautiful crimson hue.
Asparagus has abundant nutrition packed into every spear, including a range of B group vitamins, vitamin C and potassium. Add to that the emerging research that asparagus has bio-active compounds like antioxidants that help protect the body against future disease and you have a pretty impressive vegetable.
B group vitamins help the body convert fuel from the diet, such as carbohydrate, into energy. With sufficient B vitamins it is easier for us to be active and get the best out of each day. Asparagus provides the complement of thiamin, riboflavin, niacin, biotin and vitamin B6, all helping enzymes do their job in the normal metabolism of the body.
One B vitamin that is of particular interest is folate because of its powerful health benefits. For example, adequate folate during pregnancy helps Mum deliver a healthy baby (too little folate is linked to spinal deformities in babies). One serve of asparagus (3-4 spears) provides over 20% of the folate we need daily.
One serve of asparagus (3-4 spears) provides a quarter of our daily needs of vitamin C, which acts as an antioxidant and helps in the absorption of iron in the diet.
Potassium and Sodium
A diet high in potassium and low in sodium (salt), helps keep a steady heartbeat and healthy blood pressure. Asparagus has the balance right: plenty of potassium and virtually no sodium.
Iron is a very important mineral for healthy blood. Although asparagus provides only a modest amount of iron, it is high in vitamin C so the body is better able to absorb the iron that asparagus and other vegetables provide.
Antioxidants and Bioactive Compounds
Asparagus provides some powerful antioxidants, such as rutin, carotenoids (e.g. beta-carotene), flavonoids, vitamin C, saponins and glutathione, which help keep our bodies healthy now and long into the future.
Depending on what you are using the asparagus for, the following can be used as substitutes ….
- Canned <<=>> Fresh