To riff on the words of celebrity chef Anne Burrell, who says “brown food tastes good,” we can say with confidence that brown beer tastes great when done right. It’s all about those Maillard reactions.
Melanoidins, incidentally, are brown—and delicious.
The beer itself doesn’t need to be literally brown, but if we’re talking about those chemical reactions that amplify malt depth, bringing layers of comforting caramel and adding color and body at the same time, then we are getting deep into the soul of beer—and into the easily enjoyable flavors that attracted many of us to beer and brewing in the first place.
So, we’re going to focus on a neat trick for getting those deep flavors. It’s an old trick, and it’s well within the wheelhouse of any small-scale brewer—including extract homebrewers. We’re talking about kettle caramelization, a.k.a. boil reduction.
Let’s Get Deep
What do we mean when we talk about malt depth? We mean the whole spectrum of warm-hug flavors that can come from malts and their cooked sugars—honey, caramel, toffee, butterscotch, toast, and more. As we know, we can get those flavors from a seemingly endless range of specialty malts. But even if your grain bill is a little over the top, you can get even more from the magic of heat applied to your wort.
We often associate kettle caramelization with Scottish ales, especially the stronger wee heavies. Whether that has much basis in historical practice is interesting but not the point—we know that if we do it, it tastes good. Kettle caramelization can really add depth to malt-forward beer styles of all kinds—Scottish ales, sure, but also Baltic porters, stouts, barleywines, doppelbocks, and more.
In truth, “caramelization” may be a misnomer. Is it really caramelization in the kettle, or is it the Maillard reaction? The processes are distinct, but they can both happen at the same time when heat is applied directly to sugars (caramelization) as well as when it’s applied to reducing sugars in the presence of amino acids (Maillard). And malt has plenty of amino acids.
Named for the French chemist who discovered it, the Maillard reaction is the same process that gives a fresh sourdough loaf its browned crust or a grilled hamburger its browned deliciousness. As brewers, we already know what it does to beer, even if we don’t know what to call it. When “caramelizing” in the kettle, it’s really the Maillard reaction that we’re harnessing—but what’s more important is that it just works.
The most basic form of kettle caramelization is to extend the boil—for an extra hour, let’s say. That will get you more color, more flavor, and more body, as well as more evaporation. In recent years, many craft brewers have been taking that to an extreme, boiling their imperial stouts and barleywines for seemingly absurd amounts of time—for six, eight hours or more—to build up those melanoidins and increase both the starting and finishing gravities.
However, there’s another way to get added depth without boiling all your wort for many hours: a partial boil reduction.
For an all-grain batch, before the full boil, pull just a portion of the first runnings, bring it to a boil, and keep cooking it down to about 25 percent of its initial volume. Then proceed with the rest of the runoff and boil as usual.
Optionally, however—and this is a nice option for extract brewers—you can boil the reduction separately from (and simultaneously with) the main boil, then add it back to the larger portion about 10 minutes from knockout—a time saver, if you can manage two boiling kettles.
Even if you don’t give the whole batch a long, heavy boil, that cooked-down portion will lend its Maillard flavors to the rest of the beer—and that works for lighter beers as well as stronger ones.
Whoa, That’s (Wee) Heavy
There are specialty malts that can impart color, body, and caramel-toffee flavors that are something like what you’d get with a boil reduction. The result is not quite the same, but those malts can bring brilliant complexity, depth, and color to a beer. However, you’ll want to use these malts—caramel/crystal, melanoidin, and so on—in moderation. The trick is to keep the additions to a small percentage of the overall grist—no more than 10 to 20 percent in total.
There are also base malts that can bring it in higher percentages, such as Weyermann’s Dark Munich Type 2; it brings an amber hue with notes of caramel, honey, and bread, and it can be used as 100 percent of the grist.
Meanwhile, you can use kettle caramelization in addition to those malts, for added complexity. Or, you can use it in the absence of specialty malts—if you want to add some sweetness and body to a helles, for example.
For this article and recipe, I went back to an old favorite: Scottish-style wee heavy. I’ve brewed many of these over the years, but always all-grain. This time, I was thrilled to try it as a partial-mash beer, with extract and specialty malts, while taking advantage of the boil-reduction method. Going partial-mash saved me time, but to my taste the flavors were just the same as with my all-grain version. Obviously, this is a great style and technique for extract brewers to try.
The malt bill here is simple—just lots of pale malt extract and some roasted barley—so we can really taste the effect of the boil reduction. I planned for extra wort (6.5 gallons, or 25 liters), to account for the reduction. Also simple is the hop addition—just about 22 IBUs of Northern Brewer to balance the sweetness.
This may be a good place for a few words about peated malt. It’s … complicated. For years, American microbrewers and homebrewers seemed to take it as gospel that wee heavies and Scottish-style ales had to have some peat-smoked malt in there. (Many took it too far.) There was a backlash of sorts, and some still argue that those peaty flavors have no place in Scottish-style beers. The truth is more complex because Scottish brewers and maltsters apparently were using peat as fuel for the fires that dried their malts well into the 19th century; there are also accounts of those beers tasting sweet and smoky. However, many drinkers find peat-smoke flavors off-putting, and—if you’re brewing for competition—most beer judges don’t want to taste it. If you use it, know the intensity of your smoked malt and use a light hand.
Obviously, a beer like this is a great opportunity to use a Scottish ale yeast strain—I prefer Wyeast 1728. A good rule here is to ferment low and slow—a cool ferment at 62 to 64°F (17 to 18°C) over the course of two weeks.
Here’s a twist: In past wee heavies, I’ve added chanterelle mushrooms to the secondary. These bring some surprising apricot-like notes that complement the malt flavors and yeast esters. I didn’t do that this time, but it’s something to consider in your own beers. Maybe I’ll do it again in a future recipe.
Whatever you brew, the boil reduction is a great technique to consider if you want to amplify those malt flavors, body, and color, adding a complexity that specialty malts alone are unlikely to bring—and it works just as well with extract beers as it does with wort made from a full load of crushed grain.