In the early days of British brewing, malt was the only fermentable allowed by law—not from concern for “purity,” as with the Reinheitsgebot in Germany, but for a more utilitarian reason: taxes. The British government taxed brewers on the amount of malt they used. In 1847, a new tax system allowed brewers to start adding sugar to their beers. They were slow to use the new ingredient, however, and didn’t really embrace it until the 1880s.
By the 1900s, there were more than 100 specialty and proprietary sugars available to brewers. They often labeled them only vaguely in brewing records, which makes accurate reproductions difficult. Also, the brewers only rarely noted any additions of caramel coloring late in the brewing process.
That complicates historical recipes because even though we may know the color of the finished beer, it’s not obvious whether that color comes from a dark invert or just caramel coloring. In the recipes he’s re-created from old brewing records, beer historian Ron Pattinson is open about that vagueness; he picks out an appropriate invert syrup as his best guess.
Belgian Versus British Syrups
The primary difference between syrups is the production method. In Belgium, the manufacturers heat the sugar in an alkaline solution, while in Britain they use an acidic solution. While it’s true that Belgians mostly use the sugar beet as a starting point and the British use cane sugar, the differences between the refined sugars are minimal.
I have seen a few old recipes from British breweries that call for Belgian candi syrup—so, while it isn’t typical in British ales, it’s not unheard of. My view is that unless the syrup is the beer’s main flavor component—as with dark mild—you can substitute Belgian syrup for invert. In that case, I’d substitute Candi Syrup D-45 for Invert No. 2 and D-90 for Invert No. 3.
What’s the Inversion?
Heating sucrose in an acidic solution breaks the sucrose molecule into fructose and glucose, creating invert syrup—a stable syrup that doesn’t crystallize. Commercial producers invert the sugar at a pH as low as 1.9, then they adjust it back to about 6 pH after inversion is complete.
Belgian candi syrup, on the other hand, is heated in an alkaline solution, which creates different flavors from Maillard reactions. Boil temperature and length are the primary determinants of color and flavor.
Why bother with the inversion? After all, sucrose will invert itself during the boil, so why do it before caramelizing? One reason is to produce fructose, which caramelizes at a much lower temperature than sucrose. In addition, invert syrup won’t crystalize and clump like a sucrose syrup would.
The old British brewers also used invert mainly because they thought it was better for yeast health; the yeast need to spend considerable energy breaking the chemical bonds of the sucrose, and they feared it would weaken the yeast and harm future generations of pitches.
Types of Invert
There are four typical color grades of invert syrup used in brewing:
- No. 1, at 14–16 SRM/12°L, is typically used in pale ale.
- No. 2, at 30–35 SRM/25°L, is used in mild and pale ale.
- No. 3, at 60–70 SRM/50°L, is used in mild and porter.
- No. 4, at 275–325 SRM/220°L, is used in porter and stout.
The type of sugar used also makes a big difference in the syrup. The amount of impurities and amino acids present in the sugar is important. The more flavorful the starting sugar, the better the syrup will be. I usually use the Sugar in the Raw brand, but it would be fun to experiment with more exotic sugars, such as the panelas of Latin America (including piloncillo, rapadura, tapa de dulce, etc.) or Indonesian gula jawa (palm sugar).
Four Ways to Make It
There are basically four ways to make invert sugar.
The Low and Slow Way
This first technique is one I learned a decade ago from Kristen England, head brewer at Bent Brewstillery in Roseville, Minnesota.
Mix the sugar in a bit of water and citric acid, slowly heat to 240°F (115°C), and hold it there for two to eight hours until you reach the desired color. (Using your oven for this is far superior to doing it on a stovetop.) I can’t see the tiny amount of citric acid called for—¼ tsp per 2.2 lb (1 kg) of sugar—dropping the pH appreciably, but I have used this method successfully many times. The syrup made this way has a fairly clean, hard candy-like character, and it’s highly fermentable. To make a dark amber beer such as a mild, you’d need a pretty dark syrup—in that case, I suggest a full six to eight hours at that temperature.
To store the syrup for future use, you need to carefully add some water back after boiling. That will keep it at a pourable consistency; otherwise, it will solidify into a brick. Pour the cooled syrup into mason jars and store them at room temperature.
A neat trick is to divide equal amounts of the syrup into multiple jars. So, if you used 10 pounds (4.5 kilograms) of sugar, and you pour the syrup equally into five jars, each jar will have two pounds of sugar. That minimizes the need to weigh out specific amounts of thick, sticky syrup.
To help the syrups pour more easily, warm up the jars in hot water first.
The Modern Commercial Way
Modern sugar manufacturers simply add varying amounts of molasses to a golden syrup to create a range of products. My experience with molasses in beer is that it is very dependent on the quality of the molasses and the style of beer. It works much better in historical porters than in traditional mild ales.
This modern invert syrup is not the same as what brewers used a century ago, so I don’t recommend it for historical re-creations.
The Fast and Loose Way
There is a long history of heating sugar until it’s black and actually catches on fire to create what was known as essentia bina, which was used to darken porters and other beers. When commercial brewers weren’t allowed to use sugar, they would do the same with concentrated wort.
I embrace this tradition of slowly heating sugar until it’s almost smoking—it creates a very dark, flavorful syrup with notes of licorice, treacle, and toasted marshmallow.
The Way I Do It Today
These directions reflect my current method at Zebulon.
- Add the amount of sugar you need to your brew kettle at the start of the brew day.
- Add a small amount of lactic acid—about 1 ml per 3 lb (1.4 kg) of sugar—and some water—1 pint (473 ml) per 3 lb of sugar.
- Turn the heat on low.
- Stir occasionally, to keep the sugar from sticking to the bottom of the kettle. Once the sugar is dissolved, the syrup will start foaming, and then you don’t really need to stir anymore.
- Continue simmering the sugar on low while you mash and collect wort. As the syrup simmers, it will darken in color and start smelling like caramel, then Tootsie Rolls and toffee. For a lighter syrup (invert No. 1), a 20- to 30-minute boil is sufficient. For No. 2, it’s about 60 minutes, and for No. 3, about 90 minutes.
- Pay close attention when making darker versions—as soon as you see a puff of smoke come off the syrup, turn off the heat, slowly add in your wort, and proceed with the boil.
The beauty of this method is that it removes a lot of the hassle of cleanup and of trying to package invert syrup for future use. And it requires neither a thermometer nor an entire day to make.
Want to dive deeper into historical ale styles? For more from Karnowski, check out his video course, Historical Brewing in the Modern Era, or cue up Podcast Episode 155: Zebulon's Mike Karnowski Sees the Future in Beers of the Past.