This article is an exclusive online extra from the July/August 2016 issue of Zymurgy magazine.
By Amahl Turczyn, Zymurgy Associate Editor
Invert sugar is ubiquitous in the culinary world. Added to confections like chocolate ganache, fudge, and taffy, it discourages other kinds of sugars from crystallizing. Incorporated into frozen desserts like gelato, sorbet, and ice cream, it delivers a smooth, creamy texture. And invert sugar bolsters the moist, tender crumb of madeleines and brioche. Naturally hygroscopic, it absorbs moisture and lengthens the shelf lives of foods that include it.
Invert sugar also happens to make a great beer. And boiling up your own is easier than you might think.
Invert Sugar in the Brewery
Invert sugar is chemically similar to honey. While regular table sugar consists of the disaccharide sucrose, invert sugar is comprised of the monosaccharides that bond tgether to form sucrose—glucose and fructose. Invert sugar is great for brewing because yeast doesn’t have to work as hard to digest it—there’s no need to break sucrose down into its constituent monosaccharides for fermentation. But that’s not the only reason to consider adding it to your homebrew.
The Maillard (browning) reactions that take place in the production of sugar syrups can do marvelous things for beer. Traditional English and Belgian ale brewers have long relied on invert raw syrup in several color grades. The rich shades of Belgian dubbels and dark strong ales, for example, often have more to do with deeply colored sugars than they do with specialty malts.
But manipulating beer color using dark invert syrups is just the icing on the cake. Many copper- to amber-colored British mild ales and bitters were historically brewed with no colored malts at all. Color only came from the addition of dark sugar syrups, and with them, unique flavors that caramel malts just can’t replicate. The importance of invert sugar to certain styles is somewhat controversial; many accomplished brewers maintain that sugar is sugar, while others swear there is no other way to brew true British ale. But most people who taste straight invert sugar can attest to its unique qualities.
Invert sugar has a certain smoother, mellower flavor compared to other products. For brewers, invert syrup made from raw cane sugar is especially conducive to British beer styles. Beers made with this sugar seem to finish dry and clean, and they often develop subtle fruity, treacle flavors that are difficult to obtain with other ingredients. If you’ve ever tried a demerara rum (or demerara sugar, for that matter) you’ll recognize these subtle complexities.
Unfortunately, specialty brewing sugars can be difficult to find and expensive to buy. But making your own invert sugar is relatively simple and gives you control over yet another aspect of your homebrew. With temperature and moisture control, you can make invert syrups in a range of colors and flavors by manipulating the degree of caramelization, from clear white to the deepest black-brown caramel.
To be clear, brewer’s caramel and invert syrup aren’t necessarily the same thing. Just heating sugar syrup until the moisture boils out can produce as dark a caramel as you desire, and inversion isn’t strictly necessary. Yeast cells can produce invertase and split sucrose into glucose and fructose, and enzymatic inversion is a far more efficient process than acid hydrolysis.
But as long as you are heating your syrups to achieve caramelization, why not invert the sugar while you’re at it? Making caramel without inversion can actually be even more challenging, as sucrose tends to want to crystallize at the drop of a hat when the syrup’s moisture level gets low enough. In fact, many chefs add a bit of already-inverted sugar to prevent this from happening (Lyle’s Golden Syrup, for example) or a syrup with different-sized sugar molecules (as with corn syrup; in this case it’s dextrose that disrupts crystallization).
Inversion, or acid hydrolysis, is easy to do with a very small proportion of any food-grade acid, and theoretically, the less extra work your yeasts have to do during fermentation, the healthier they will be. Happy yeast makes better beer.
Making Invert Sugar
In the inversion process, a solution of sugar is heated in the presence of an acid until it reaches 236° F (114° C). Clear invert syrup starts with white sugar and is heated very slowly to minimize Maillard reactions that would otherwise develop color and flavor in the syrup. Once inverted, this pale, corn syrup–like sugar can be refrigerated and stored for months.
Use a relatively unprocessed cane sugar for maximum flavor. Raw cane sugar—with variations such as turbinado, demerara, and evaporated cane crystals—all work well, each contributing a slightly different character to the final product. Plain white sugar, be it cane, beet, or otherwise, tends to disappear into beer, bolstering alcohol, drying the finish, and lightening the palate. That’s just the thing with styles like Belgian golden strong ale and West Coast IPA, where caramel, dark rum, and raisin characteristics are unwanted. The clear stuff is probably also the confectioner’s and baker’s choice. We’ll start there, then focus on the dark side.
Begin with a heavy, deep saucepan. Add 2 cups (473 mL) carbon-filtered water, 2.2 lb. (1 kg) white cane sugar, and 1/4 teaspoon (1.23 mL, usually about 1 g) of food-grade acid. The acid can be potassium bitartrate (cream of tartar), citric acid, or even ascorbic acid if you have some vitamin C handy. If you prefer a liquid preparation of 88% lactic acid, use 3 mL (just over half a teaspoon). Brave souls and purists can stop there, but I strongly recommend adding about 4 tablespoons of corn syrup or Lyle’s Golden Syrup as added protection against crystallization.
After mixing it with water, the sugar will be wet and slushy. Add low to medium heat to begin dissolving. Slow, gentle, even application of heat is the best way to avoid the biggest issue with syrup-making: crystallization. You want to go slowly enough to make sure all crystals disappear into solution before the syrup boils. Chefs often say to use a wet pastry brush to wet down any sugar crust that forms at the side of the syrup; I’ve found a spray bottle or mister does a good job here as well. Just know that the more water you introduce at this point, the longer it will take to get to the correct temperature.
Shut Up About Marlin Perkins
Recipe by Amahl Turczyn
- Original gravity: 1.044 (11° P)
- Final gravity: 1.005 (1.3° P)
- Bitterness: 34 IBU
- Color: 10 SRM
- Alcohol: 5.1% by volume
- Boil time: 90 minutes
Ingredients for 5.5 gallons (20.82 L)
- 2.5 lb. (1.47 kg) Maris Otter pale malt extract syrup (44.8%)
- 2 lb. (0.9 kg) Six-row pale malt (27.6%)
- 1 lb. (0.45 kg) Dark #3 invert cane sugar (13.8%)
- 1 lb. (0.45 kg) Flaked corn (13.8%)
- 75 oz. (21 g) First Gold pellets, 7.5% a.a, (60 min.)
- 1 oz. (28 g) East Kent Golding pellets, 5% a.a, (30 min.)
- 1 oz. (28 g) East Kent Golding pellets, 5% a.a, (5 min.)
- 1 oz. (28 g) East Kent Golding pellets, 5% a.a, (dry hop, 7 days)
- Wyeast 1318 London Ale III yeast
Mash 2 lb. (0.9 kg) six-row pale malt with 1 lb. flaked corn for 45 minutes at 153° F (67° C). Drain, rinse grains, and dissolve 3.25 lb. (1.47 kg) Maris Otter malt extract syrup in the resulting wort. Add invert cane sugar to kettle before boil, stirring to dissolve it into the wort completely. Add hops at stated intervals, chill, and aerate. Ferment at 68° F (20° C) or until terminal gravity is reached. Add dry hops and condition one week at cellar temperatures (50–56° F or 10–13° C), then package.
Omit extract and six-row. Mash 1 lb. (0.45 kg) flaked corn with 6 lb, (2.72 kg) Maris Otter pale malt for one hour at 153° F (67° C). Sparge until wort gravity reaches 1.008 (2° P) or runoff pH falls to 5.8, whichever comes first. Add invert sugar and proceed with boil as above.
Dip a candy thermometer in the syrup and monitor the temperature until it hits at least 236° F. Keep the heat low and be patient. The syrup may bubble up and expand to four times its original volume as it thickens, so make sure you have plenty of room in your saucepan. Also, take proper safety precautions: syrup boils hotter than water, tends to spatter, and can inflict heinous burns. Once it reaches your target temperature, you can be done. If you’ve begun with white sugar, your invert syrup should be nearly clear, and you can use it in the kitchen or in pale beer styles. Jar up the hot syrup in lidded heatproof jars and store them in a cold place.
If you want a little more flavor and color, you can repeat the procedure using raw cane sugar. From the beginning, you will notice a light tan color in the syrup; this will darken further if you allow the syrup to cook long enough to caramelize. Keep the syrup simmering, and as water evaporates, the temperature will ramp up progressively faster over time. Eventually, if you let it cook long enough, it will approach the “hard crack” range of 300–310° F (149–154° C) and reach a deep, reddish, cola-brown hue of roughly 80° L at 310° F (154° C).
Before you get there, at around 300° F (149° C), back the heat off to very low, as you are perilously close to burning the sugar. You may even catch whiffs of burnt sugar towards the upper range. Of course, this is the extreme end of the color scale for the syrup; you can certainly stop the heating process at any point between 236° F and 310° F (113 to 154° C), to tailor the amount of color and flavor desired.
British brewers traditionally graded their invert syrups into three shades. Brewers invert #1 syrup was 12–16° L (orange-amber), invert #2 was 30 to 35° L (amber-bronze), and #3 was 60-70° L (reddish-black). Each will contribute unique and interesting flavors and aromas to your beer, so it’s well worth making several shades of syrup and experimenting with different combinations in your beer.
Regardless of when you choose to stop heating the syrup, when you’ve achieved your desired color, turn off the heat and allow the syrup to cool. What you have just made will either form a heavy syrup, a chewy, taffy-like “soft ball” candy, or a rock-hard sheet if you’ve taken it all the way to “hard crack.” So to keep things manageable, either pour the molten candy into a silicone or parchment-lined metal pan to cool (no wax paper or foil—it will stick), or dilute it back to a lighter syrup. For hard candy, you can break up the glass-like sugar into pieces, and store it in an airtight container for direct addition to the kettle.
But it’s easiest to just return whatever grade of invert sugar you’ve made to a syrup again. Boil one to two more cups of filtered water and add the hot water back to the sufficiently cooled candy. (By ”sufficiently” I mean closer to 200° F/93° C than 300° F/149° C— the higher temperature will create an explosive boil-up of steam.) Add the boiling water slowly and stir carefully until you’ve reached a syrup consistency again, then jar it off in heatproof, lidded jars. Your invert, caramelized brewing syrup should keep several months refrigerated. Make several grades of syrup and have fun experimenting with them in your beers!
If in the course of your experiments you happen to produce a near-black, 60–70° L invert #3-type syrup, you may wish to give the accompanying recipe a whirl. It’s the sort of ale (what we’d now label a “best bitter”) London breweries made back in the 1920s, and it makes the very best use of homemade, dark invert cane syrup.
- Jackson, Michael. Michael Jackson’s Beer Companion, Duncan Baird Publishers, 1993.