There's a fascinating article on brewing sugar in the latest IBD magazine. The editor visited Ragus, the manufactures of the big blocks.
Brewers commonly use invert sugar, that is sucrose (a disaccharide) that has been split to its constituent monosaccharides glucose and fructose. The received wisdom in the industry is that invert sugar is better for brewing with, as saving the yeast from having to invert it itself stresses the yeast less. I've always thought this sounds dubious but I could be wrong. The article lists the benefits of invert sugar as:
- Reduced crystallisation
- Higher concentration and more stable - Golden Syrup [an invert sugar] is 83-84% sugar, with an 18 month shelf life
- It is sweeter than sucrose so less can be used to get the same level of sweetness
- Sucrose needs breaking down by yeast to ferment so invert is more readily fermentable
- Readily available to make colour, flavour and texture
"The sugar cane refining process produced a treacle-like syrup that usually went to waste. In 1883, Charles Eastick, a chemist at the Abram Lyle & Sons (now part of Tate & Lyle) refinery in Plaistow formulated how it could be refined to make a preserve and sweetener for cooking."So the fact invert sugar was made from a waste product and can be made to a high concentration (the maximum concentration of sucrose syrup is 67%) sounds a more likely reason for why it became popular with brewers to me.
There are some differences between the brewing sugar syrups and blocks Ragus make:
"in liquid form they consist of 95% invert and 5% sucrose, while in crystalline block form they contain 75% invert, 5% sucrose and 20% wheat-derived glucose. They are all 95% readily fermentable ... and with extract values between 321.5 L°/Kg and 326.5 L°/Kg"Brewer's Sugar No.1 is subtle in colour (25-35 EBC) with a mellow flavour.
Brewer's Sugar No.2 is amber in colour (60-70 EBC) with a strong flavour.
Brewer's Sugar No.3 is dark brown in colour (120-140 EBC) with a rich flavour.
Brewer's Sugar No. 4 is very dark in colour (550-650 EBC for blocks, 625-724 for the syrup) and is derived from caramel rather than the dark cane sugars Nos. 1-3 are made from.
There are also Ragus Brublocks, containing the same amount of extract but made from 75% glucose coloured with cane molasses (No.1 and 2) and caramel (No.3). These are less fermenatable with 80% of the extract readily fermentable, 4% slowly fermentable and 16% unfermentable. Other products include a Dark Brewing Syrup (2875-3375 EBC), glucose chips and priming sugar.
Brewing sugar use has declined in recent years, though as Harvey's and Timothy Taylor are customers of Ragus there's no doubt it can be used to make world class beers. Ragus only sell by the tonne, but is it available 25kg at a time from bakery wholesalers so perhaps its use will start to creep up. It's a handy way of increasing your wort gravity and/or extending your brewlength after all.