Candy Professor

Beer and Candy, yet again

January 23, 2013 at 9:39 am Leave a comment

One of the surprises in my candy research has been the intimate and unexpected connections with liquor. Brandy drops and the like barely scratch the surface. Take, for example, the case of invertase.

Invertase is one of the candy chemist’s little secrets. It is an enzyme that splits sucrose (table sugar) into smaller pieces: glucose and fructose. You can buy invertase from kitchen chemical supply companies. It is used to make fondant smoother. And most important, invertase is the magic ingredient that makes possible dipped chocolates with liquid centers. Confectioners start with a solid, fondant center made with invertase; after the solid center has cooled, the invertase goes to work and within a few days, the fondant has turned to liquid.

Invertase sounds like a scary chemical additive, but actually it is active in all kinds of natural processes. It is what helps bees transform nectar into honey. And each of us carries around our own personal supply, right in our own mouths as part of the chemistry of saliva.

Invertase was first discovered by nineteenth century chemists who were studying the effect of yeast on sugar. They noticed that the sugar changed form before it started fermenting, and eventually they isolated the enzyme that caused this effect. By 1900, processes for deriving invertase from yeast were well known, and over the next decades chemists would develop many uses for invertase derived from yeast, most importantly in candy-making.

And where did that yeast come from? Some of it may have come from factories like Fleischmann’s that were manufacturing yeast for home and commercial baking. But some of it came from breweries.

Yeast is a by-product of the beer brewing process; when the beer is done, the yeast settles at the bottom of the tank. Storage and re-use is possible, but there are some difficulties. Instead of throwing it away, some brewers’ ended up donating or selling the waste to be turned into invertase.

One chemist, by the name of Sidney Born, was able to complete his 1913 dissertation on the chemical constitution of invertase thanks to the generosity of the Jacob Ruppert Brewery, who furnished Born with 200-pound barrels of compressed yeast from time to time. Born describes a complicated and tedious process lasting several weeks; eventually, 200 pounds of yeast would yield 200 grams of invertase.

Based on Born’s process, I calculate almost a pound-for-pound transformation from yeast to finished candy product. Candy makers using invertase undoubtedly accounted for a huge quantity of brewery waste after Prohibition ended.

So there you have it: from beer to candy, via the chemistry lab, and a nice story about industrial recycling as well.

Sidney Born, The Chemical Constitution of Invertase, 1913 at Google Books

Entry filed under: Candy Making, Ingredients.