Avoiding the Harsh Zone

Beer brewing is an art, and not just a technical exercise, as my friend Randy Mosher is fond of reminding me. Many of you know Randy as the author of great books like Radical Brewing and Mastering Homebrew, but he is also an accomplished graphic artist who approaches beer design from a much different perspective than my own engineering brain does.

A few years ago Randy approached me with some draft portions of his recent book Mastering Homebrew. He made the observation that there are relatively few kilned or caramel malts made in the color zone between 70 °L and 200 °L. The reason for this is that malts in this “harsh zone,” when used in excess, have unpleasant properties and flavors like burnt toast, burnt marshmallows, tannic bitterness, and harsh tones, which overpowers a beer.

Types of Malts

To understand the harsh zone, we first need to understand the different type of malts and how they are made.

The malting process starts with raw barley grain. The raw barley is typically immersed in water, bringing its water content up high enough to get the seed to germinate and sprout. The grains are allowed to grow for a few days until the small shoot, called an acrospire, reaches a length roughly equal to the length of the grain itself. Small rootlets will also form outside the grain, though these will fall off and be separated during kilning.

The grains are next dried, though the method used varies depending on the type of grain being produced:

• Base Malts (1–10 °L): Base malts such as pale, Pilsner, Vienna, and Munich malts are kilned at low heat. Typically, moisture is reduced to under 10% when kilning and often English malts are dried further.

• Kilned Malts (10–70 °L): Malts such as amber, melanoidin, honey, and brown are kilned and dried in the same process as base malts, initially at low heat, but then the temperature is raised significantly once the grains reach a certain dryness level to produce a darker malt with many base-like properties with few or no enzymes.

• Kilned Caramel Malts (1–150 °L): After the malt has been wetted and the acrospire has formed, it is transferred to the kiln, but not immediately dried. Instead, the temperature of the wet malt is raised to about 122 °F (50 °C) to begin a stewing process that mashes the sugars within the husk. Slowly, the temperature is raised to approximately 150 °F (66 °C), converting most of the starch in the grain to simple sugars. The grains are then dried in a kiln where the temperature can also be raised to produce darker caramel malts, much as we produce darker kilned malts. Non-homogeneity in the kiln bed leads to very dark malt on the bottom (exceeding 150 °L) contributing harsh notes even at moderately colored kilned caramel malts (above 60 °L ).  The caramel malts contain longer sugar chains called dextrines, which add body to the finished beer as they do not fully break down during fermentation. However, overuse of caramel malts can produce sickly sweet, unbalanced beers.

• Roasted Caramel/Crystal Malts (1-120 °L): Green malt is transferred from the germination compartment to the roaster where a relatively high level of moisture is retained in the malt during a conversion process that simulates a mini-mash occurring inside each kernel. Once conversion is complete, the malt is dried, and the product temperature is increased to achieve the desired color and flavor. Unlike caramel malts produced in a kiln, roasted caramel malts are homogenous and have a uniform, crystalline endosperm. The flavor of roasted caramel/crystal malts range from caramel, toffee, sweet to burnt sugar, roasted marshmallow, dried fruit.  Green malt roasted beyond 120 °L may enter the “harsh zone” where it will take on a woody, dark toast, coffee flavor.

• Roasted Malts (200–600 °L): Roasted malts are made by taking dried base malts and putting them in a drum roaster to be roasted at very high temperatures. The key to making great roasted malt is not only choosing the right temperature and point to stop roasting, but also rapidly cooling the grains when the appropriate roast level is reached. There is one exception, which is roasted barley, also called stout roast, which is made from unmalted barley roasted at very high temperatures.

Harsh Zone Malts

Mosher defines malts in the 70–200 °L color range to be “harsh zone” malts. This includes many popular dark crystal malts such as caramel/crystal 80 °L, 100 °L, and 120 °L, as well as Special B (which is also a caramel malt) and some malts on the edge of the harsh zone like brown malt and pale chocolate malt.

Used in small quantities, these malts can add dried fruit, plum, chocolate, mocha, coffee, toasted marshmallow, and caramel flavors. When overused, they result in flavors like burnt toast, burnt marshmallow, campfire character, and harsh tannic flavors akin to sucking on a tea bag.

A common “beginner” mistake, for example, is to add crystal 80 °L (or darker) malts to something like an English brown ale to darken the color. Often the beer will take on a very harsh finish and unpleasant character, as a relatively large portion of this moderately colored malt must be used to achieve a brown color. This is very common for extract brewers, who tend to use dark crystal and light roasted malts interchangeably. Malts in the harsh zone have unique flavors that should be used with caution and with the intention to add flavor rather than color. The following are generalizations about “harsh zone” malts and may not apply to every malt on the market with a similar name. Unique production methods will dictate the flavor of a malt, so it is suggested to familiarize yourself with a malt’s extractable flavor contribution before brewing.

Let’s look at each of the malts in and around the harsh zone, and the flavors you can achieve from them:

• Melanoidin Malt: A kilned malt that is generally below the harsh zone. Melanoidin malts are typically kilned in the 25–35 °L range but a few dark examples may be kilned up to 60 °L. Melanoidin malt is often used by brewers to “simulate” the malty flavors one might get from a decoction mash, and tends to impart a strong malty finish, with hints of biscuit and honey. Some variants take on a red hue, and most varieties of melanoidin are unlikely to impart harsh off-flavors due to the low color range, and are typically used for 3–10% of the grist.

• Brown Malt: Also a kilned malt that is on the lower edge of the harsh zone at 60–70 °L. Brown malt was once the base for traditional porter styles, though it is rarely used these days. It has a dark toasted grainy flavor and imparts mocha and bitter chocolate flavors. If used in excess, the bitter chocolate flavor can dominate and take on tannic, burnt grain, burnt toast, or burnt coffee notes. I like to use this malt in robust porters, but generally keep it below 5% and combine it with other dark specialty malts to add complexity and depth.

• Kilned Caramel/Crystal 80 °L: In my opinion, this is probably the most overused and abused harsh zone malt, as many brewers use it to “add color and body” to a recipe, not knowing that they are significantly altering the flavor balance. Crystal 80 °L, unlike its lighter siblings, takes on more of a burnt sugar flavor with hints of raisin and caramel. In small quantities, raisins, figs, or caramel will come through, but used in large quantities, the burnt sugar can be
quite pronounced.

• Caramel/Crystal 100–120 °L: These malts have an intense roast sugar flavor, and can be quite bitter with a Turkish coffee finish. Used in small amounts you will get toasted raisins or figs, but overuse will lead to acrid bitter and burnt flavors.

• Special B 120–140 °L:  Special B is technically a very dark Belgian crystal malt usually roasted to 120–140 °L in color. It can have flavor elements of both the very dark crystal 120 °L malt and also light chocolate malt. Used sparingly you can get toasted raisin, figs, cherry, or plum notes from it. In large quantities you will get a pungent burnt sugar flavor along with acrid bitterness from tannins.

• Light/Pale Chocolate Malt 200–250 °L:  From the name, one might assume
that this is merely a lighter, gentler version of chocolate malt. While the color is indeed slightly lighter than chocolate malt, it actually imparts a more piercing coffee-like roast flavor to the finished beer. Because this malt is right on the edge of the harsh zone, it is more sharp and piercing than chocolate malt. Used in large quantities, you will often get harsh burnt-coffee flavors along with tannic bitterness akin to sucking on a tea bag. In small quantities, however, it can give a nice coffee-like finish particularly when combined with other specialty malts.

• Chocolate Malt 350–400 °L (and Carafa® I): Though these malts, like melanoidin, are outside the harsh zone, they do take on some of the sharpness and bitterness you will find in light/pale chocolate malts. In fact many people don’t know that chocolate and Carafa® malts are more piercing and bitter than black malt. These malts tend to be bittersweet, sharp with a coffee character, and bitterness can be dominating if used in large proportions. They taste nothing like chocolate! Carafa® tends to be a bit smoother than chocolate malt.

Using Harsh Zone Malts

Here are a few rules of thumb to consider when adding harsh zone malts to your beer:

• Don’t use harsh zone malts for color: I avoid using harsh zone malts when I want to just add a bit of color to my beer. You are better off using either lighter crystal or kilned malts, or alternately very small quantities of chocolate, black patent, or stout roast. The darker roasted malts, in particular, can add significant color with only a small amount of malt that won’t throw off your flavor balance.

• Use harsh zone malts sparingly: Harsh zone malts are great flavor additions, but you need to use small quantities — typically 3–5% of your grain bill. For example, Special B will really help add depth, plum and raisin notes, and complexity to a porter or stout, but if you use too much the burnt sugar, burnt marshmallow, and acrid bitterness will come through.

• Use malts with a purpose: Avoid the “kitchen sink” approach to beer brewing where you add every malt in your cabinet to a recipe thinking it will make great beer. Make sure each ingredient has a purpose and fits the style and flavor profile you are trying to create.

A Harsh Zone Example

Harsh zone malts are very appropriate in certain styles of beer. For example, I enjoy adding them to stouts and porters, particularly English versions, as they create complexity and depth. Here’s an excerpt malt bill from a recent robust porter I brewed:

87% Maris Otter pale malt
3.6% Caramel malt (60 °L)
3.6% Special B
3.6% Chocolate malt
2% Black patent malt
47 IBUs from Centennial hops
White Labs WLP002 (English Ale Yeast)

My intention here was to create a complex, robust, slightly sharp porter with some depth and complexity, perhaps riding the line between a robust porter and a stout.

The Maris Otter base provides a strong foundation of English malt with a lot of character to it, and notice that nearly 90% of the malt bill is base malt. You don’t need to add 20–30% specialty malts to create a beer with depth of flavor. Caramel 60 °L gives the beer some English maltiness and character, but is also dark enough to provide some fruit hints without being overly harsh.

Special B is the only harsh zone malt, and it provides depth as well as character. At 3.6% of the malt bill it is enough to bring out toasted raisin, prunes, and some bitter notes without being overwhelming or creating burnt or tannic bitterness. The Chocolate malt provides a strong roast finish to the beer, and finally just a bit of black patent gives the beer a roasty edge that you might expect in a
robust porter.

To balance the beer, which is a bit edgy, I did hop with Centennial at a pretty high hop rate (47 IBUs), and then finish it with an English ale yeast, again to accentuate complexity, esters, and a slightly malty finish. I chose Centennial over a traditional English hop because I enjoy its aroma/flavor profile and it has enough alpha acids to deliver the bitterness needed.

After brewing, the beer did deliver the “robust porter” complexity I was looking for. Though I used only one harsh zone malt, that combined with the caramel 60 °L and chocolate malts from just outside the harsh zone plus a dash of black patent gave the porter some real depth. It’s not a one-dimensional beer, but instead has layers of flavor, which you can achieve by combining harsh zone malts with other specialty malts in appropriate proportions. Centennial fit in well with the beer, providing enough bitterness and flavor to offset the strong flavor profile of the malt.

I’m using the lessons learned from this beer for a Russian imperial stout that I hope to blend with mead to make a braggot. By stepping up the base malt, black patent, and chocolate proportions and swapping out brown malt for the caramel 60 °L, I should be able to get a very strong, rich imperial stout that can stand up to blending with a sack mead.


I encourage you to work hard to become familiar with the flavor profiles of all of the major malts available whether they are base malts, caramel malts, kilned malts, or roasted malts. Each malt has its own unique character, aroma, and taste, and unfortunately many malts are “misnamed” in that their name does not represent the flavor that is to be expected from them. A sensory evaluation is needed in order to fully understand the extractable flavor contribution of your malt.

Harsh zone malts can be a powerful tool if you are aware of their strengths and weaknesses and harness them to create great beer. Key concepts include the idea of having a clear purpose for every single malt you add to your grain bill. Use specialty grains sparingly, especially those in the harsh zone. Develop depth by combining a handful of specific flavors rather than adding everything but the “kitchen sink.” Finally, don’t use harsh zone malts to just “add color” to your beer, as this will destroy your flavor balance.