The Magic (and Science) of Making Marmalade
It is hard to say when marmalade as we know it became popular in Britain, but before a rather fuzzy period of its history it was known as ‘marmelos’, a thick, sugary, mass of quince fruit paste that was popular in Portugal and Spain. Orange peels also used to be preserved in sugar syrup as a ‘sweetmeat’. Similar treats are still common in tavernas and bars around the Mediterranean. Oranges cooked into the bitter-sweet jelly that we know as marmalade started appearing around the 1750. Home making of marmalade has since become popular throughout the country. Mrs Beeton has recipes in her 1861 edition, and there are many other records of recipes. Who doesn’t have family recipe books with favourite marmalade recipes?
Although British marmalade usually refers to any citrus fruit made into a jam, the classic marmalades are made with Seville oranges. There are many different ingredient combinations and variations on the procedure, but that all draw on the same basic principles. The marmalade draws on the high Seville pectin content (mostly in the white pith of the peel), the acidity in the bitter juice, and the addition of sugar plus heating to achieve an extraction and combination of the pectin and flavours into a heavenly, glowing gel. For the cook, it involves a loving ritual of slicing, mixing, heating, and stirring. Then anxiously waiting for and judging precisely the ideal point at which the pectin will cool to set as a perfect gel that will sit on toast and show off the clean colours and transmogrifying gastronomic orgasm that comes through eating the marmalade.
The background molecular magic that results in the pleasure is worth a close look as it determines the recipe ingredients and the cooking methods for success. The Sevilles have a unique combination of strong, orange-flavour and a compelling bitterness that enhances the flavour. They also contain a high level of pectin, a class of plant cement that helps keep the plant cells together and working properly. Pectin is a long chain polysaccharide. It is at its highest concentration just before ripening then is broken down as fruits ripen. For jam makers, this pectin makes the jam into a jelly instead of only a runny liquid that would just flow off your toast and down your chin. To make the marmalade jelly, you need this pectin, a low acid environment, and sugar. The oranges have pectin and the acid in the juice. Heating the chopped fruit in water dissolves the pectin and the long chains break into smaller units. The water helps break down the pectin chains into smaller chains, and gives these pieces negative charges that further push the pectin pieces away from each other. The water also dilutes the pectin pieces so there is less tendency for the longer chains to reconnect.
The acidity in the Sevilles (or with added lemon juice if the Sevilles are very ripe) helps by balancing the negative charges with positive charges so the broken chains don’t repel each other so much. The sugar isn't just to sweeten the jam. Its role is more interesting. Sugar molecules attract water from around the pectin chains, making them closer together so the broken chains can start getting closer together again. In so doing, they form a gel as they cool and, BINGO, the hot sugar and fruit solution starts to form a gel ...and....that’s marmalade.
At home you can identify this setting point with a thermometer or by the easily learned skill of pushing your finger through some of the boiling jam that has been placed on a cool plate to cool down. If setting point is reached, you see the ‘wrinkling’ of the surface from the gel starting to form. One interesting feature of the heating the sugar and chopped fruit mixture, is that the formation of the gel occurs at a temp of between 103-105 0C. Pure water boils at 100C, but the dissolved sugar helps push the boiling temperature to the setting point and this sugar concentration will be about 60-65% by weight. The interesting fact is that there is a wide range of tolerance between the amount of juice, added water, and sugar in the recipe. With Sevilles, there is usually enough pectin and acid in the fruit so the water will boil away until the sugar concentration reaches about 60-65% and that pushes the temperature up to the setting point and the marmalade will set.
The difference between adding say two parts sugar to one part fruit weight compared to equal parts of sugar and fruit is first that the 2:1 mix will be sweeter and less orange flavoured than the 1:1 ratio (which will have more orange flavour and sweeteners with bitterness), and the 2:1 will give you 3 parts weight of sweeter marmalade to only 2 parts with the 1:1. For me, I have no hesitation choosing the fuller flavour with less sweetness, even though I get a little less weight of marmalade….but what marmalade!!
The pleasure in making marmalade at home is getting the best and just under-ripe, juicy fruit, and adding the right amount of water and sugar to the chopped fruit, before heating at the right intensity while watching for that setting point to just appear. Then removing the marmalade from the heat and bottling it correctly. There are many combinations of the basic ingredients that will give you perfectly acceptable marmalade to suit your own taste. Make it a few times or share with friends and you will soon find out your preferred recipe. In the next marmalade blog I’ll show you some very different recipes from some rather famous food writers too show you how variable the recipes can be to give a choice of marmalade pleasures.
Do you have any questions for Christopher?