The blackcurrant (Ribes nigrum) is a woody shrub in the family Grossulariaceae grown for its piquant berries. It is native to temperate parts of central and northern Europe and northern Asia where it prefers damp fertile soils and is widely cultivated both commercially and domestically. It is winter hardy but cold weather at flowering time during the spring reduces the size of the crop. Bunches of small, glossy black fruit develop along the stems in the summer and can be harvested by hand or by machine. The fruit is rich in vitamin C, various other nutrients, phytochemicals and antioxidants. Blackcurrants can be eaten raw but are usually cooked in a variety of sweet or savoury dishes. They are used to make jams, jellies and syrups and are grown commercially for the juice market. The fruit is also used in the preparation of alcoholic beverages and both fruit and foliage have uses in traditional medicine and the preparation of dyes.As a crop, the blackcurrant suffers from several pests and diseases. The most serious disease is reversion, caused by a virus transmitted by the blackcurrant gall mite.
Another is white pine blister rust which alternates between two unrelated hosts, one in the Ribes genus (blackcurrant included) and the other a White pine. This fungus caused damage to forests when the fruit was first introduced into North America, where the native white pines have no genetic resistance to the disease. As a result, the blackcurrant has for most of the 20th century been subject to restrictions in parts of the United States as a disease vector.
The effectiveness of these restrictions is questionable, since other Ribes species also host the disease and are native to North America.Breeding is being undertaken in Europe and New Zealand to produce fruit with better eating qualities and bushes with greater hardiness and disease resistance.On a garden scale, the berries should be picked when dry and ripe. Commercially, most harvesting is done mechanically by straddle harvesters.These move continually down the rows, straddling a row of bushes, shaking the branches and stripping off the fruit. The blackcurrants are placed into half tonne bins and to minimise stoppage time, some machines have cross conveyors which direct the fruit into continuously moving trailers in the adjoining row. A modern machine can pick up to fifty tonnes of blackcurrants in a day using only one operator and two tractor drivers. For culinary use, the fruit is usually cooked with sugar to produce a purée, which can then be passed through muslin to separate the juice. Blackcurrants are a common ingredient of Rødgrød, a popular kissel-like dessert in North German and Danish cuisines.
Blackcurrants are also used in savoury cooking because their astringency creates added flavour in many sauces, meat and other dishes and they are included in some unusual combinations of foods. They can be added to tomato and mint to make a salad, used to accompany roast or grilled lamb, used to accompany seafood and shellfish, used as a dipping sauce at barbecues, blended with mayonnaise, used to invigorate bananas and other tropical fruits, combined with dark chocolate or added to mincemeat in traditional mince pies at Christmas.Japan imports $3.6 million of New Zealand blackcurrants for uses as dietary supplements, snacks, functional food products and as quick-frozen (IQF) produce for culinary production as jams, jellies or preserves.