Munich Malts Explained

The differences among specialty malts is confusing for a number of reasons, including how the same description, such as Munich or crystal, is used for a wide range of malts. And some maltsters use creative names, for example a German-sounding word or a word with an oddly placed umlaut, to suggest a malt type. Let’s start diving into your question by first digging into the typical process used to produce Munich malt.

All malt types share commonalities through the “green malt” phase of production. Green malt is the term used to describe germinated grain kernels before the kernels are dried. To produce green malt, maltsters steep barley to increase moisture content from about 8% to about 45%. Steeping not only turns on metabolic processes, it also washes the surface of the dry kernels, floats away light debris and chaff, leaches polyphenols/tannins from the grain husk that can inhibit germination, and delivers oxygen to the grain embryo. Various steeping and aeration methods are used by maltsters because steeping sets the stage for germination and no one approach works for all. Indeed, most maltsters declare steeping to be the most critical step of malting.

By the end of the 36–48 hour steeping process, the hydrated kernels have entered the “chit” stage of germination as seen by the emergence of a rootlet from the embryo end of the kernel. The chit malt is either transferred to germination or the steep tank is drained and prepared for use as a germination vessel. Equipment aside, the germinating barley is attended using a combination of periodic turning, blowing cool and moist air flow through the grain bed, and/or spraying water on the surface to the bed. These methods help maintain temperature, moisture, and oxygen uniformity within the germinating “piece,” or lot, of germinating malt. Turning also helps prevent rootlets from tangling and individual kernels from being collected into masses that make germination control difficult. Germination times vary based on the primary control parameters of moisture content and temperature, but most malt spends 3–5 days in germination. Particulars aside, green malt exits germination and is either transferred to a kiln or roasting drum.

Before moving into kilning, let’s take a brief detour into the topic of color development and Maillard browning. The cascade of chemical reactions between so-called reducing sugars and free-amino groups during cooking are collectively described as Maillard browning, or sometimes “the” Maillard reaction, and the products of these changes are known as Maillard reaction products (MRPs). Technical details of the reactions aside, higher protein grain, increased moisture content after steeping, increased malt modification, and a moderate, high-moisture step during kilning all increase the concentration of reactants that lead to MRPs. Maltsters like to use the term “levers” when referring to these process variables they can “pull” when producing malt. More on this to follow.

In general, Munich malts have more color, more flavor intensity, especially with respect to malt aroma, a higher degree of modification, and usually are less enzymatic than lighter base malts like Pilsner malt. Maltsters achieve these differences by pulling on the levers that increase MRPs, especially degree of modification and kilning profile. The ratio of soluble protein to total protein, referred to as the Kolbach Index (KI) or S/T in the malt world, is one index of modification that is also directly related to the concentration of free-amino nitrogen (FAN). As green malt FAN increases, so do MRPs. This is why Munich malts have higher S/T ratios than lighter malts produced by the same maltster. Increased malt modification also increases reducing sugar concentration, but not by much.

Kilning regimen is key to Munich malt production, and the big levers in kilning that maltsters pull are high “air-off” moisture during the early stages of drying (this is accomplished by recirculating air during kilning to increase the piece temperature without losing moisture) and a prolonged curing time at ~212–221 °F (100–105 °C) for color and flavor development. Pilsner malt, as a comparison, is gently kilned without any intentional delay in drying, curing time is shorter and curing temperature is lower to minimize color development. In general, Munich malts have more biscuit, dark bread, and nutty aromas than Pilsner and Vienna malts, the color typically ranges from about 5–20 °L (12–52 EBC or 6–12 SRM), and the enzyme content is usually high enough for 100% inclusion. The uses for Munich malts are very broad, making this general classification one of the most commonly used specialty malts in brewing.

OK, now for the discussion about color you probably have been waiting to read. To make things less confusing, ignore adjectives used to describe color because malt color is numerically defined. Descriptors like light and dark don’t provide any more information than color values and often confuse things because one maltster’s light Munich may be another’s dark Munich.

Another confusing thing is the wide range of color found beneath the Munich malt umbrella. Given that Munich malt is named after a German city, let’s take a look at Munich malts produced by three German maltsters. Weyermann has three conventional (not organic) Munich malts with colors of 6, 8, and 9 °Lovibond. Bestmalz produces two conventional Munich malts with colors of 6 and 11 °Lovibond, and Ireks produces a single conventional Munich malt at 8 °Lovibond. It looks like the German maltsters keep Munich malts within a pretty narrow color range; not a huge surprise considering the precise nature of German malting and brewing.

Traveling across the pond to North America, Munich malts with higher colors are found. Briess produces 10, 20, and 30 °Lovibond Munich malts and Gambrinus makes 10 and 30 °Lovibond Munich malts. Not sure why North American maltsters push colors up, but it probably has something to do with really pulling on the levers! Just like with beer where triple imperial IPAs were needed because the garden variety IPA was too pedestrian, dark Munich malts from Germany apparently needed more umph.

The interesting thing with these darker Munich malts is that their recommended upper grain bill limits are much less than the 100% cap on Munich malts from Germany. And that of course is because the kiln lever was pulled hard enough to denature enzymes. North American 20 and 30 °Lovibond Munich malts don’t list enzyme values with their malt certificates of analyses (COAs) because there is really nothing to report; these darker malts may be called Munich but they don’t share the enzymatic strength of their European ancestors.

Finally, there are products with Munich in the name that are not “Munich malt” as discussed earlier. Weyermann produces three malts in their Cara family of products called CaraMunich® (I,II, and III). The Swaen maltings from the Netherlands has their family of GoldenSwaen© caramel malts and produce GoldenSwaen© Light and Dark Munich malts. It’s clear by reading about these products that they are not Munich malts, nor are they marketed as such. But the word Munich stands out in their names and it appears that some homebrewing retailers have misclassified some special malts with Munich in their names as “Munich malt” types.

For a practical takeaway, the best way to evaluate malt for brewing, especially malts that are used for their beautiful colors and special flavors, is to taste the malt and/or prepare a malt tea using the ASBC hot steep method (or an abbreviated facsimile). Lots of great information can be quickly unveiled using malt sensory. Thanks for the terrific question!

Response by Ashton Lewis.