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Introducing Malt and the Malting Process

Seeds are simply a w

Introducing Malt and the Malting Process

Seeds are simply a wonderful invention of plants. They contain the embryo, and enough well stored food to start the cycle of life. The stored food are the long chained starches. Enzymes contained in the grain, called amylases, which are produced through malting and activated by the addition of water during mashing, are responsible for cleaving the long sugars into usable shorter disaccharides (mainly maltose). The process of malting can be summed up by the germination of barley, or other cereals, up to a certain point and then the new-born malt is passed on to the kiln. It is at this point that the decision to make a certain type of malt manifests itself in the temperature of the kilning program that will follow. The kilned malt contains activated amylases that are awaiting re-hydration to carry out their work of making maltose, and other sugars, such that at a later point in time the yeast have something to ferment yielding alcohol. The temperature of the kilning will define the target of the malt produced, achieving the expected colour through the Maillard reaction (high temperature reaction leading to the development of a large spectrum of caramel like overtones). Both tastes and aromas are created in the kiln and are passed onto the beer in the mashing process.

Malt can therefore be divided into 3 broad categories: base malts, crystal or specialty malts, and roasted malts. Base malts retain high amylase activity (diastatic power) due to the temperature not being high enough to denature them and high sugar content, thus making up a large majority of the grain bill. Below we provide details about several malt types. We include descriptive details and flavour wheel profiles.

The specialty malts (CaraMünich and other Caras) are kilned at around 121°C during a specific period of time; the longer the kilning lasts the more caramel characteristics are developed. Given the large spectrum of “crystal” malts it is appropriate to study them and choose the correct one for the style and flavour preferences that you may have.

We are not presenting all malts, but the present exercise should allow you to independently find the information and interpret given profiles according to your desires.

Before proceeding further, we would just like to mention the concept of making beer roughly 5,000 years BC. It was no doubt a series of accidents, but it is quite easy to imagine that the first “brewers” simply had forgotten their barley in a stone vase and it rained. The vase now (2-3 days later) contained malt. Naturally occurring yeast were also on the barley such that fermentation spontaneously started.  Nice how nature has provided us with this nice little package that has subsequently become more complex, but can also occur with minor intervention by man (the brewer).

The data brewers can access about their malt is usually readily available on the maltster’s homepage or if you directly as them for their analyses. This data will help you develop your grain bill rather accurately and be able to estimate with precision how to reach your targets and what results you should get in terms of sugar, colour, etc.

Base Malt

As the process of steeping and germination is similar for all cereals, it is during the kilning phase, and the different temperatures applied, that each type of malt produces its particular colour and flavour. The production of base malt, the least modified type, starts with several stages of drying between 50 and 65°C (free drying and forced drying) of the green malt (pre-kilned malt), which has moisture levels between 42% and 45% after germination, until it reaches moisture levels of around 5%. Then starts the curing phase, which will determine the type of malt produced, at temperature ranging from 84°C (modern lager malt) to 100°C (classic ale malts) for several hours until moisture reaches 3-4%.

Brew Malt






Pale Ale

5.5 – 7.5

2.6 – 3.5

Ales, Stout, Porter

Up to 100%

Produces superb lagers and ales


Specialty Malt

Also known as Crystal malts in the US, have undergone higher modification than base malts. This means that the green malt is sent directly to the roaster rather than the kiln. They are first heated at low temperature to dry them off to a certain level, then heated anywhere between 80 and 145°C depending on the target colour and flavour.

Brew Malt







60 – 80


Bock beer, dunkel ale, brown ale, red lager, amber ale, amber lager

Up to 20%

Improved flavour stability, promoted fullness, enhanced colour, full red colour, better mash efficiency, notes of toffee, caramel and bread

Roasted Malt

Roasted malts are finished malts that have undergone a further roasting step at temperatures as high as 230°C. The higher the temperature and the longer the roasting, the darker the finished malt. These malts already have a great impact on the finished beer with very little addition in the grain bill.

Brew Malt






Carafa 3



Stout, dark beer, alt beer, porter

Up to 5%

Deeper aroma of dark beers as well as beer colour

Formulating a Grain Bill

To properly work through the formulation of a grain bill one has to understand the different characteristics provided by each malt type; mainly diastatic power, extract potential, flavour and colour. Maltsters provide extensive documentation on all of their products (as seen above). Studying these documents is essential to knowledgeably make decisions about which malts and their relative proportions to include. We give you now several formulas that will help you build the backbone of your recipe, namely the grain bill.

Malt quantity

First question to ascertain is the malt quantity necessary to obtain the targeted original gravity. More modified malts will give slightly less sugar than, say, base malts. However, the difference being minimal we will simplify the calculation by considering all malt used gives out the same extract. Thus:

Volume of post-boil Wort(l) x Original Gravity(%) x Density / Efficiency(%)

In this formula, we must use both the gravity in ° Plato and the density in specific gravity. Let us therefore use an example a target final volume of 50l of wort at 12 Plato:

50 x 12 x 1,048 / 70 = 8.98kg (we can round it up to 9kg)

We use in this example 70% brewhouse efficiency, which is a good target to try to attain. Now, this efficiency can be adapted in the calculations if it appears that you usually hit lower sugar levels than calculated, or vice versa.

Out of these 9kg we can then decide the percentages of each grain we would like to use. These can be decided by looking at the recommendations made for each malt type by the producer. To continue with our example above we have decided to split the grain bill as follows:

Pale Ale = 80% = 7.2kg

CaraAmber = 15% = 1.35kg

Carafa III = 5% = 450g

Diastatic power

Measured in degrees Lintner, it represents the starch-converting enzyme activity of any given malt. The importance of base malts as the highest proportion of a grain bill is correlated to their high diastatic power. Indeed, a 2-row Pale malt has, for example, 110°L, when a Wheat malt has 120°L. The 6-row Pale malt even goes up to 160°L. However, crystal and roasted malts, due to the high kilning temperature, have completely lost their enzymatic power. It would therefore be impossible to build a grain bill with 50% caramunich 3 and 50% carafa 3. In such an extreme situation, the mashing process will not yield any saccharification and none of the starch will be cut into smaller chain sugars. It is considered that above 30°L the mash is self-converting. However, you should aim for a minimum of 70°L in the total grain bill to have optimal conversion.

Let us use a case study to better understand how to work out the diastatic power of a mash:

7.2kg Pale Ale at 160°L

1.35kg CaraAmber at 0°L

450g Carafa III at 0°L

We first multiply each quantity with their respective power, thus:

7.2 x 160 = 1152

1.35 x 0 = 0

0.45 x 0 = 0

Total = 1152

Now let us divide the total power by the total weight:

1152 / 9 = 128°L

As we are here way higher than the minimum required diastatic power we know our grain bill will yield enough enzymatic activity to convert all the starch.


With each malt that you use one can find a colour rating either of EBC, Lovibond or SRM. They are inter-convertible terms so we will provide the EBC colour profile. It goes without saying that, the more modified the grain, the darker its colour impact on the final beer.

Calculating it can be tricky and might slightly differ from reality. However, it is still a good measure and the steps to take are two-fold; firstly, we need to ascertain the Malt Colour Units (MCU) of the grain bill. These can be calculated as follows:

MCUs = Weight(kg) x Lovibond x 2.205 / Volume(l) x 0.264

Where 2.205 converts kg to pounds and 0.264 litres to gallons, as it seems that this formula only works with these units.

Now let us continue with our recipe and volumes:

Pale Ale: 3.5°L (Lovibond), 7.2kg

CaraAmber: 27°L, 1.35kg

Carafa III: 500°L, 450g

Calculating the MCUs:

MCUs Pale Ale = (7.2 x 3.5 x 2.205) / (50 x 0.264) = 4.2

MCUs CaraAmber = (1.35 x 27 x 2.205) / (50 x 0.264) = 6

MCUs Carafa III = (0.45 x 500 x 2.205) / (50 x 0.264) = 37.58

TotalMCUs = 47.78

Now we must convert these MCUs in predictable colour. The formulas being in the SRM format, we will first calculate SRM with the Morey version, then convert to EBC:

SRM = 1.49 x MCU0.69

SRM = 1.49 x 47.780.69 = 21.47

Converting to EBC is simply a matter of multiplying by 1.97:

EBC = SRM x 1.97

EBC = 21.47 x 1.97 = 42.29

We hope that with these basics you will be able to build your recipe without the use of a brewing software, which is very useful but less satisfying than manually calculating your targets.

Good luck!


Malt: A practical guide from Field to Brewhouse. John Mallett (Brewing Element Series) December 2014

Designing Great Beers

Ray Daniels



Weyermann Specialty Malts


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