Learning Lab: The Foundations of Malt

Base malts are the foundation of beer. It’s worthwhile to have a sense of the trade-offs your extract supplier made. As a bonus, this mini-batch experiment is a good introduction to mashing.

Jester Goldman May 7, 2019 - 11 min read

Learning Lab: The Foundations of Malt Primary Image

When we say that base malts are the foundation of a beer, we mean that they will contribute the bulk of the sugars for the yeast. They usually make up most of the grist, and they supply enough enzymes to convert their own starches as well as those of any additional specialty grains or adjuncts.

At a high level, three factors differentiate these malts: modification, diastatic power, and color. Modification refers to how accessible the starches are within the kernel. Today, most brewing malts are well-modified, meaning that the maltster let the kernel sprout long enough to start breaking down the barriers to accessing the starch. Earlier in brewing history, malts were much less well-modified, so multistep mash processes were developed to assist things.

Diastatic power defines how much alpha and beta amylase the grain provides, which determines how effectively it will convert its own starch along with that of any adjuncts or specialty grains. (Recall that alpha amylase chops long starch chains up and beta amylase nibbles the ends into fermentable sugars.) A base malt with lower diastatic power, such as Vienna malt, will still be able to convert its own starches, but it might be challenged by larger percentages of non-base malt.

As part of the malting process, the grain is kilned after sprouting and an initial period of growth. The kilning temperature and time affect the color, so different base malts will show some visual distinctions.


Types of Base Malts

Barley falls into two main families, 2-row and 6-row (the names describe how the kernels are arrayed on the stalk). Large commercial brewers tend to favor 6-row, which has smaller kernels but higher diastatic power. Those two barley families expand into six different base malts, each of them with their own character, but most of these are made with 2-row barley.

2-Row Pale Malt Most of the barley malt available to homebrewers is 2-row, but in the case of pale malt, we’re talking about the lightest kilned version. Two-row pale malt is very light, about 2° Lovibond (L). It has fairly high diastatic power. This is a solid, understated base malt.

6-Row Pale Malt
The 6-row version of pale malt is similarly light in color but has an even higher diastatic power. This makes it a better match for beers that have a lot of adjuncts, such as American light lagers. Some people report that 6-row pale malt has a sharper flavor compared to 2-row.

Pilsner Malt
Pilsner malt is usually less modified than straight pale malt, and it’s typically a little lighter in color. As the name suggests, it’s primarily used in Pilsners, but many Belgian beers also use it as a base. When not covered up by specialty malts, Pilsner malt has a distinctive soft sweetness that often has a honey-like character.

Pale Ale Malt
Pale ale malt’s name is easy to confuse with plain pale malt, but this 2-row barley is kilned at a higher temperature, making it about twice as dark as pale malt. It contributes a more pronounced maltiness, sometimes with biscuity or toasty character and often a light nuttiness. It works well for all but the lightest beers (by color and/or flavor).


Vienna Malt
Vienna malt is well-modified, but its diastatic power is lower. As a result, it doesn’t support a lot of adjuncts on its own, but you can punch it up with some regular pale malt. Like pale ale malt, it’s more heavily kilned, yielding more color and rich malt character. I think it’s better at providing toasty character. While its sweet spot is Vienna lagers and Oktoberfests/märzens, it works well in almost any amber beer.

Munich Malt
Munich malt is more typically used as a specialty grain, but it does have enough diastatic power to convert itself. At about 6–9°L, it’s quite a bit darker than the other base malts. That color is indicative of the complex maltiness it contributes. As a base malt, Munich malt works best in a dunkel or Oktoberfest.

Time to Experiment

To compare these base malts, we’re going to brew a set of 1-gallon (3.8 l) mini-batches using a simple recipe. We’re aiming for something like a blonde ale but without worrying too much about nailing the style. We’ll follow a single-step brew-in-a-bag (BIAB) process, so you won’t need much extra equipment or experience with all-grain brewing.

This experiment is fairly scalable. If you want to make all six test batches, that’s great. At a minimum, you should include the 2-row pale, the pale ale malt, and the Pilsner malt in your experiment.

Our recipe is dead simple. Try to get in the ballpark with the hops, but it’s more critical that each batch is the same and that the hops aren’t overwhelming.


Volume (after boil): 1 gallon (3.8 liters)
OG: 1.052
FG: 1.012


2 lb (907 g) crushed base malt
0.25 oz (7 g) Cascade pellet [7.0% AA] at whirlpool
1/2 packet of Safale US-05 yeast


Place the crushed malt into a nylon grain bag and set aside.

Heat 3 qt (2.8 l) of water to 158°F (70°C). When the water reaches temperature, move the pot off the burner. Dip the bag of malt into the pot and swirl it around. Your goal is to make sure that all of the grain is thoroughly wet.

Check the temperature of the liquid. We’re aiming for 152°F (67°C). You may need to heat the liquid a little or add a splash or two of cool water. In either case, stir the bag in the pot to normalize the temperature.


Once you’re at the target temperature, cover the pot and let the grain bag sit. In winter, you may want to wrap it in a blanket for insulation. We want to mash for about 60 minutes, but you can check the temperature halfway through. If it has dropped more than a couple of degrees, you should put it back on the burner to kick the temperature back up.

At the end of the hour, heat up another 2 qt (1.9 l) of water to 170°F (77°C). Lift the grain bag out over the pot (if you have a strainer that can sit on the edge of the pot, that would be great). Pour the hot water over the grain and into the pot to rinse a little more of the malt sugars out.

Top up the pot with another quart (946 ml) of water. Boil the wort for 1 hour, then take the pot off the burner.

Stir the hops into the wort for a whirlpool addition. Cover and let sit for 20 minutes. Then chill the wort to 70°F (21°C), transfer into a gallon (3.8 l) jug, topping up with water if necessary. Pitch the yeast and put on the airlock.

Ferment each mini-batch at about 70°F (20°C) until FG is reached. Once fermentation is complete, bottle the batch with about 0.4 oz (12 g) total dissolved priming sugar.


Evaluating the Differences

After the beers have each had 2 or 3 weeks to carbonate, it’s time to evaluate the differences. In this case, pay attention to aroma and flavor first, then get a sense of the mouthfeel. Finally, compare the colors across the spectrum of base malts. If you’ve been following this series, you should be familiar with our tasting protocol; just remember to write down your impressions. Pour the beer and focus on the aroma. What do you notice on your initial sniff? Does that change as you spend more time sinking deeper into the aroma? While you’ll certainly notice the hops and maybe some of the fermentation character, take special note of the malt. You may pick up on hints of bread, bread crust, toast, nuts, or honey.

Now, take the first sip and hold it in your mouth for a moment before swallowing. Give it some time to settle before you take another taste. Look for malt flavors that complement the aroma. How sweet does it seem? Take a deeper draught and swallow quickly. Does the malt bring anything to the finish, such as a lingering sweetness? How does the beer feel in you mouth? Is it thin-bodied and watery? Or does it have a richer mouthfeel?

Once you’ve tasted each of the samples, contrast them with one another. Does the 6-row pale malt have a sharper character than the 2-row pale? Can you pick up the characteristic sweetness in the Pilsner malt batch? Do you get more of a toasty note from the pale ale malt? This is also a good time to look at the array of glasses. How does the color vary? Does the line-up match expectations: Pilsner malt, pale malt, pale ale malt, then the Vienna and the Munich?

Think about how all of these differences would fit the beers you want to brew, whether by style or even just flavor profile.

Next Steps

Once you’ve got a good sense of the base malts, you might want to go for extra credit and run the same experiment on a single base malt from different maltsters. It could be interesting to see how much difference there is between Breiss, Rahr, and Weyermann, for instance. It’s particularly good to compare pale ale malts. Each company has its own process and schedules, and these can vary more with pale ale malt.

Finally, if you’re an extract brewer, consider trying this mini-mash approach to brew a more interesting beer recipe. If it goes well, you might want to attempt a full all-grain batch.