Lime marmalade

The production of traditional lime marmalade is perfectly feasible and the general principles for jam making apply. Lime however, does present one unusual problem owing to its very high acidity. It will have been noted that the pH of a preserve has to lie between 3.0 and 3.3 in order to obtain a good stable gel (or 'set').  Most fruits lie in this pH range.  Those above 3.3 require the addition of citric acid to bring the pH down to the required range.  Lime juice however has a pH of 2.7 to 2.9 and so the PH has to be increased.  This, it has been found, can be easily done with sodium bicarbonate (baking powder). These notes are based on work carried out in the West Indies.  It should be remembered that minor modifications to the formulation may be needed in other areas where different varieties of lime may be grown. This technical brief explains the procedure of making lime marmalade.