Rheum rhabarbarum L.
Also called the “Pie Plant”
Rhubarb is a cultivated herbaceous perennial of the genus Rheum. Its grown for its long fleshy and red leaf stalks (petioles) which are edible. The roots and leaves are not edible.
The rhubarb plant has large somewhat triangular leaves that grow from short thick rhizomes (stems). The leaves contain high levels of oxalic acid, are highly poisonous and should not be eaten raw or cooked.
Rhubarb belongs to the dicotyledonous family Polygonaceae together with Buckwheat (Fagopyrum esculentum), sorrel and knotweed.
Cultivated Types of Rhubarb
Rhubarb is either grown in the green house (hot house rhubarb) or in the field (field grown rhubarb).
The hot house rhubarb has pink or light red stalks and somewhat yellowish leaves. The field grown rhubarb has dark red leaf stalks and green leaves.
With regard to taste, the hot-house type is somewhat milder in taste, sweeter and is less stringy.
The field grown rhubarb is extremely tart and can be stringy, especially the mature grown ones.
Culinary Use of Rhubarb
Although rhubarb is botanically considered a vegetable, its fleshy leaf stalks (petioles) are used as a fruit, in pies, crumbles, cakes, muffins and sauces.
The leaf stalks can be mild to extremely tart flavour and should be sweetened with sugar, honey or maple syrup to make them more palatable.
Rhubarb can also be paired with sweet fruits like apple, pear or strawberries or stewed in orange, pineapple or apple juice. Dried fruits like raisins, sultanas or currants, can be added to the stewed fruit or pie or crumble.
Spices like ginger, cinnamon, pumpkin or mixed spice or star anise, can be added to enhance flavour. Vanilla extract (essence) or fresh vanilla, can also be added.
Half a cup of cooked unsweetened rhubarb has only 29 calories but once it’s sweetened, the calories can be as high as 140, depending on the amount of sugar added.
Preparing Rhubarb for Cooking
For Hothouse rhubarb, wash and trim the top and bottom and cut into 1-2-inch lengths for stewing or sauce making
For mature field grown rhubarb, you may need to remove the stringy fibres from the stalk, after trimming. To remove the stringy fibres, use a paring knife as you would with mature celery stalks.
Cut up 500g (1Ib) rhubarb and place in a glass baking dish. Sprinkle with 1/3 cup sugar (or to your taste) and cover tightly with aluminium foil. Bake for 30 minutes at 300ºF (150) or for 15 minutes at (350ºF (180ºC) or until tender, stirring once. Taste and adjust the sugar to your taste.
Do not cook rhubarb in Aluminium or cast iron skillets. Use non-stick, or enamel coated cookware.
Remember that rhubarb will taste sweeter after cooking, so add the sugar when it’s almost cooked. Taste the rhubarb to gauge how much sugar you need. You can also add honey or maple syrup, after cooking, to your taste.
Place 500g (IIb) cut up rhubarb in a non-stick pan and add 2 tablespoons water (or orange, pineapple or apple juice). You can also add some orange or lemon zest or vanilla for flavour. Cover, bring to the boil and simmer, gently until tender, about 6-8 minutes. Remove the cooked rhubarb from the pan then reduce the left over liquid over high heat and pour the thick sauce over the cooked stalks.
If you want to stew it to a pulp or sauce then you’ll need to cook it longer (15-20 minutes). You can add cornstarch (cornflour-UK) or arrowroot powder to thicken the sauce.
A lot of recipes recommend 100g (½ cup) sugar per pound (500g) of rhubarb, but it’s a matter of personal taste so add the sugar to suit your palate.
Use stewed rhubarb as a topping or filling for cakes or serve with ice cream, custard, yoghurt or whipped cream.
For low-fat rhubarb “fool” stew the rhubarb with some sweet fruit, sweeten and chill then serve with low fat yoghurt.
Pureed and sweetened rhubarb can be served over chicken breasts, sliced fruits or cutlets.
Shopping for Rhubarb
Rhubarb is sold in loose stalks or in 1Ib cello bags like celery.
Choose well-coloured, good sized, straight, firm leaf stalks that will snap on bending.
If the leaves are attached, they should look fresh and crisp. Smaller leaves, have younger, more tender stalks.
Storage of Rhubarb
If you buy rhubarb with leaves, you should cut off the leaves as soon as you get home.
Place the stalks in a plastic bag and store in the refrigerator crisper for about one week. The leaves should never be eaten, raw or cooked.
Availability of Rhubarb
Field grown rhubarb can be bought from April-June or July.
Hot house rhubarb is harvested from January through to June but some supermarkets have them all year round.
Rhubarb can also be sold frozen. Frozen rhubarb is available all year round.