| Simmer the pearl barley in a litre of water for about 45 minutes, or until tender. |
| Simmer for a further 1-2 minutes, stirring occasionally, until the pineapple sauce has thickened, then leave to cool. |
| Simmer for 10 minutes, leave to cool and then strain the mixture through a sieve into a large jug. |
| Simmer until the mango is soft and mushy and most of the vinegar has evaporated. |
| Simmer the cooking liquid until reduced to four cups, skimming the surface as needed to remove any impurities. |
| Simmer for five minutes before skimming off any scummy bits gathered on the surface. |
