The Secondary Flavors of Malt | Craft Beer & Brewing Magazine
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The Secondary Flavors of Malt

With a wide array of flavors that are imparted by simply using different malts and grain, the flavors in beer have never been more specific or diverse. From light and sweet flavors, to roast and smoke, the flavors in between continuously delight the palate

Josh Weikert 24 days ago

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No one sets out to make a bad beer. When we brewers sit down to work up a recipe, we can be almost comically optimistic about the likely result. We may well draw up a plan to create precisely the beer we want, using processes we’ve honed over hundreds of batches, and taking care to consider all of the steps necessary to avoid the pitfalls and perils waiting for us, in terms of off-flavor creation. Despite these best intentions and our conscientious plans, though, we often indulge blind spots in flavors and impressions that are predictable and intrinsic to the malts we’re using. One of the most common examples might be DMS in Pilsner malt, but that’s really just the tip of the iceberg.

It’s not that we don’t know what our malts taste like, necessarily—instead, it’s that we read the headline and ignore the rest of the story. Few malts only taste like one thing, and just like some love the bright fruitiness of Simcoe while ignoring the sulfuric, catty addition caused by thiol, most of us are guilty of getting (and passing on) more than we bargained for in the malts we include in our grist. This article will outline some of the secondary (or even tertiary) flavors and effects to be on the lookout for the next time you put together a new recipe or update an old one!

Light and Sweet

Starting with the palest of pale malts, let’s talk about Pilsner malt. A common feature of far more than just the Pilsner styles, Pils malt is often described as providing a light and grainy flavor, which of course it does. You might also see descriptions of it as “lightly sweet” or “honey-like”—don’t write off those descriptions.

To many palates, Pilsner malt adds a noticeable sweetness that isn’t unlike the kind of saccharine flavors we attribute to the lightest caramel malts, and for the same reason: as lightly kilned as it is, it has little in the way of contrasting flavors to offset that honey-like impression. Whether or not it’s actually sweet, it certainly seems so, and in beers without sufficient balance from darker malts or bitterness, it can be off-putting. It might be worth your while to include a pound of something just a bit darker (Maris Otter, Vienna) in your base grist, just to be on the safe side. And, of course, watch out for that DMS by giving yourself at least an uncovered 45-minute boil (it’s a little elementary to point out, but the reminder can’t hurt).

In that same vein, let’s talk about another malt that adds honey-like flavors: I’m speaking, of course, about honey malt. This malt is almost stupidly sweet. Even a few ounces into a five-gallon batch can be too much, especially if you’re sensitive to the flavor. I’m not exaggerating when I say that adding actual honey to a beer has far less of a flavor impact than honey malt, for most varieties (all the more so since honey is almost 100 percent fermentable).

Bottom line? Don’t assume that it’s only the darker malts that are bringing something unexpected or intense to the table.

The Strange Relationship of Crystal and Oxygen

This one is almost like Greek or Shakespearean tragedy. Take a malt. Process it in such a way that it creates a compound that actually takes up oxygen. Then, without warning, you find out that [CUE ORGAN CHORD PROGRESSION] the same malt can actually accelerate staling and oxidation. [CROWD GASPS]

Now, hard science on this is hard to come by, but there’s a growing impression among brewers that significant use of crystal and caramel malts can accelerate oxidation and rapidly erode hops character in beers, under certain circumstances. This, as noted above, is ironic, since caramel and crystal malts usually develop as part of their production an increased melanoidin level—and melanoidins are powerful antioxidants. However, there are three caveats here that might make you think twice. First, as the caramel and toffee flavors of medium crystal malts themselves oxidize, they often take on far richer dark fruit and raisin flavors, which tend to mask other flavors (especially brighter hops flavors). Second, in cases where melanoidins are themselves oxidized pre-boil—stale extract or malt, cracked-but-not-mashed grains, etc.—they actually form compounds that facilitate and speed up the production of other oxidized compounds. Last, when labs look for evidence of decreased oxidized compounds in the presence of high levels of melanoidin, they often strike out.

For that reason, many breweries are avoiding caramel malts (especially crystal 60L), particularly in their hoppy beers. The scientific jury is still out, but in the meantime, maybe use caramel malts a bit more sparingly.

Roast and Smoke

I truly, deeply love roasted malts. If I have an excuse to put a roasted malt into a beer, I almost certainly will. I also really love smoked malts, and I nearly always brew a Rauchbier rather than an Marzen, if given half a provocation to do so. Having said that, these are also two malts that are more subtle than they seem at first glance.

We all know about the addition of coffee and chocolate that comes from adding roasted malts (250L and up). There’s some misunderstanding, though, about just how to use them that I run across from time to time. As a reminder, remember that you’re adding more than just roast flavor—you’re also likely adding dryness, perceived bitterness, acidity, and possibly astringency. That’s in the realm of basic brewing knowledge, though. Where we might go off the rails is in thinking that the depth of the roasting has a specific, linear relationship to just how intense the flavor is, which can yield some really unpleasant recipes.

Brewers should generally stick to 10 percent or less of any roasted malt—though under the right conditions, I’ve been at (and just over) 15 percent and still been fine. More than that, and I’ve been burned (pun intended), as have many others whose beer I’ve tasted. Here’s the thing, though: that percentage seems to hold true even when we’re talking about lower-Lovibond roasted malts.

Early in my brewing life I made a brown ale with 20 percent pale chocolate malt—and it was like drinking a charcoal briquette. I thought I’d be fine, though, because I had recently brewed a big, roasty beer with about 10 percent 550L black malt and another 5 percent of chocolate rye. Surely, then, a few extra points of the 300L pale chocolate should be fine, right? Wrong. Since then, I’ve experimented with different kinds of recipes, balancing ingredients, alcohol levels, and more—and whatever the Lovibond of the grain (high or low), as I edge over that 15 percent figure, things start to go sideways. There are even a number of times I’ve used predominately black malt or roasted barley and had a much less patently roasty beer than when I’ve used paler roasted malts, potentially thanks to the “flavor-simplifying” effects of longer roasting.

Interestingly, the opposite seems to be true of smoked malts. When first brewing my Rauch, I was warned not to use too much smoked malt, for fear it would be overly smoky. Okay, then—I started with 40 percent. Then 50. Then 75. What I found was that there was only a marginal (and barely noticeable) increase in perceived smokiness in each version. So, now I brew my “R-97” Rauchbier with 97 percent beechwood-smoked malt (sometimes with a bit of oak-smoked wheat for fun, but still with an overall “smoked” percentage that’s through the roof). What seems to hold up much better as a point of consideration is not the percentage of smoked malt but rather the wood used to smoke the malt. Beechwood is good. Cherry is good. Oak is fine, but I wouldn’t go as far with it.

Mesquite is…well, it’s nearly undrinkable, as I found out recently when I was warned not to use more than a couple of points of it. That’s one gallon of beer I’ll never get back.… Long story short, though (too late), is that you shouldn’t fear the amount of smoked malt—fear the smoke itself.

Sensory Confusion

We get yet another abject lesson in humility when asking our senses to pick out what we intend to get out of malt vs. what we perceive we’ve gotten out of it. I used to use Special B in my Doppelbock until I had three different people ask me why it was “Belgian” or pointed out that they perceived “some kind of ester—are you sure this is a lager?” Apparently, the raisin and currant flavor was triggering thoughts of hot fermentations and Flemish yeast strains. Rich, bready melanoidin aromas can (apparently, because I’ve done it) be mistaken for diacetyl—I had to train the sensory hook out of myself with a healthy serving or six of Old Speckled Hen (which, for those who’ve never tried it or noticed, is an absolute showcase of diacetyl). The spicy notes in rye can be confused for all kinds of things, but less so in the presence of a lot of hops character or a richer malt base.

Is some of this idiosyncratic? Sure. But it highlights what I’m positive is a global problem that brewers face, which is that what people perceive isn’t necessarily what’s actually there. You can train up your own senses using flavoring kits from Siebel and others, and you absolutely should do so, but that doesn’t protect you from others’ perceptions. The moral of the story? Even when a malt has a clear flavor, try to discern if there are any ways to misinterpret it and consider recipe adjustments to account for them.

Construction and Reconstruction

Finally, consider flavors that can be created due to treatment (or mistreatment) of the malts you’re using. In no particular order: “Husky” or raw grainy flavors can be derived from overlong mashes; anything over 90 minutes might get you a flavor you won’t like. Some also claim that this flavor can come from over crushing malt before it goes into the mash, but several award- winning “Brew in a Bag” folks I know quite literally powder their grains, and don’t see that effect, so I’m not sure I buy it. Old malt—or, more likely, malt that is crushed and then not used for several days—will absolutely dull the flavor of malts (especially more-intense character malts) and also introduce metallic and/or papery flavors, just like post-boil oxidation. This is different from “hot-side aeration” and the debate that revolves around it, since we’re not talking about oxygen introduced in the mash, but rather to staling of the ingredients themselves before they ever touch the water. This can wreck a recipe because not only are the off-flavors unpleasant, but the dull flavors of your specialty malts can really throw off the balancing effects we might want from them.

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