Scanning the labels of packets, tins and bottles in a supermarket, it is amazing how often grasses or their products appear in the ingredients - sweetcorn kernels, cane sugar, corn oil, beer or whisky, lemon grass and even a tub of icecream, not to mention all the pastas, breads and cakes made with flour. Look out for starch, dextrin and dextrose; these are often obtained from maize (Zea mays).

Sugar from stems

Most of the world’s sugar comes from the stems of a giant grass. Sugarcane (Saccharum officinarum) usually grows in the hot humid tropics. It probably originated in New Guinea, but was taken to the Americas by Christopher Columbus on his second expedition there in 1493. Visit Kew’s Palm House to find out more about it.

Another grass grown for its sweet sap is sorghum (Sorghum saccharatum). Crushing the stems releases the sugar-rich sap which is boiled down to produce a rich golden syrup called sorghum molasses. In parts of the southern USA, particularly Kentucky and Tennessee, people pour it over pancakes or biscuits or add it to gingerbread or baked beans.

In Brazil more than 4 million cars are powered by fuel containing ethanol made by fermenting sugar from sugarcane.

Cereal to real ale

Lager, bitter, pale ale and stout are among the many different kinds of beer brewed from a single cereal - barley (Hordeum vulgare). The first stage in making any barley-based beer is to germinate the starchy seeds under warm moist conditions. This process, called malting, releases enzymes that break down the starch to sugars. Yeasts then ferment the sugars to produce alcohol. Brewers add hops to give the characteristic bitter flavour.

In Japan, sake is made from rice (Oryza sativa) which is mixed with a special fungus to start the brewing process. The Mexican beer chica is made from maize (Zea mays). Its name comes from the Spanish word for saliva, as the beer-makers originally chewed the grains, so that their saliva began the conversion of starch to sugar.

Malt whisky is also made from barley. It goes through a similar process of malting and fermentation, before it is distilled and aged in special wooden barrels to develop its distinctive flavour.