The Biochemical Levers That Explain Malt
Photos courtesy Rahr Malting.
Happy St. Patrick’s Day! I have a very special post for you—and it has nothing to do with the holiday. Rather, it’s the second part of my promised two-parter on malt that began way back in early February with the pFriem-Rahr collaboration that produced To Thee malt. Just to refresh your memory, we were talking with pFriem’s Director of Brewery Operations Campbell Morrissy, who has a Ph.D. in barley breeding and genetics, and Rahr’s Matt Letki, who has an education and background in brewing. They explained why pFriem needed a new pilsner malt, and what challenges that request posed. In today’s post, we’re going to address a question I’ve entertained for well over a decade: does a base malt’s flavor come from the barley variety or the malting process?
The day I arrived at pFriem to interview Matt and Campbell, I posed this very question to Matt as we were waiting for Campbell and he offered me a fantastic answer that will function as the overview for this post. He told me:
“Barley varieties are important. However, the concept that this barley variety has this specific flavor and that flavor comes out of the process is not really accurate. Barley varieties have different biochemical levers, different protein ranges, different enzyme balances. Those, combined with the art of the maltster, create a product that has the flavor precursors that a brewer needs to create the right beer. It’s not that you’re going to have the flavor of this one barley variety that carries from the field all the way through. The barley variety is really important, but it’s not the flavor from the barley in that equals the flavor of the malt out. It’s these biochemical parameters which the maltster can then coax through the amount of moisture in the kernel, the germination temperature and time, the kilning, all this stuff the malster can really use to optimize the process to create the malt. For malt flavor, it’s more about the parameters that have been built into the malt, including flavor, that go into the malting process.”
One way to think of it, and something Campbell and Matt returned to throughout our discussion, is that it’s better to think of malting and brewing as connected processes. If you recall our previous conversation, the maltster has many choices to make, all related to the “biochemical levers” Matt referenced. It’s very much like the choices a brewer makes on mash pH, mash temperature, the number of rests and so on. It’s not like there’s a “correct” mash temperature; brewers make choices based on what they want out of a beer. The same is true with malting, and it’s why one brewery might choose a malt where one set of choices was made, while another brewery would want a different set.
With that overview, I found it quite valuable to hear Matt describe the malting process so you can get a sense of what those levers are. This is all taken directly from Matt’s description, polished up a little bit for clarity.
Cleaning the Barley
“Barley comes in from the field. It's an agricultural product, and we don't have lily-white clad maidens picking the berries off the barley plants, right? So it comes in and there's, you know, bits of broken kernels and twigs and seeds and all kinds of other things that come in with it. We've got to clean that material out, so we're going to put it in water, which is the steeping process. We’re getting rid of polyphenols, tannins, getting rid of dust, we're getting rid of all kinds of stuff.”
Steeping and Germination
“Then we move into germination. Some barley varieties will uptake water more quickly than others, different protein ranges will uptake water more quickly. So every different barley variety that we malt—and we malt them all separately—they all respond slightly different to the inputs of air, temperature, water, in the malt house at a time. Generally speaking, we can moderate the temperature. So if the water's too cold, we can warm the water, but we're looking for very consistent kind of temperature. It takes about four days. It's all relatively consistent, and the way when you're running a malt house, you get into a cadence, and you can't really vary too much. So it's a four-day germination. It's a one day for steep, essentially, four days for germination, and another day or so for kilning.”
Here Campbell added a comment:
“And just to chime in on the breeding component, that's another challenge of breeding, right? The industry used to have longer germination times. And now the industry is really pushing for four-day germination. So breeders have to make sure that they're selecting varieties that can germinate properly and modify properly within that four days. You’d have the best yielder out there, and if it’s a six-day germ, you've just thrown off an entire production schedule.”
Matt picked it up from there to continue on with germination:
“So then we move into germination and the temperature of germination, the amount of water we’re applying during germination. And that’s all that goes in, is temperature, air, and water, during germination. That’s it. Everything else that's needed to make malt is already present in the kernel. So, again, the different barley varieties respond differently to those inputs, and the maltster has to understand the barley variety, understand those idiosyncrasies and really play with process to make the right material to go into kiln; to have the right amount of solubleized protein, the right breakdown in germination, the right moisture—everything to go into kiln.”
Moisture Content
“Then critically, we don’t want too high of a percentage of moisture, what’s called the LTK, the ‘load to kiln.’ The load to kiln moistures really need to be trimmed for post-malt.” [Matt explained that the more moisture is in the kernel, the longer it will take to kiln, which means the more color it will take on in the process.] “You can't have, like, a 48% moisture, which you might if you're making a pale ale malt, for a pils malt. You need to be in that 42% kind of range. So you have less water that you need to burn off in kilning, because more water means more energy, which means more color through melanoidin creation.”
The final stage is kilning, which we were discussing in terms of pilsner malt.
Kilning
“One of the key things about malt is we don’t want to ship our customer a whole bunch of water. So the malt has to be dry. And when you get to that final cure stage in malting, if you have a nice dry malt, you can lift the temperature up through kilning, and then we hit it at a final cure stage to lock in the flavor, to really build out the final kind of flavor of the malt.” He continued later: “Every malt house is unique, right? Because every malt house has slightly different technology, just like every brewery has slightly different technology, and the way they achieve boil. So each malt house is slightly different, and then each malt that is produced is slightly different, and each batch is going be slightly different.”
Along the process, the maltster will make different choices to adjust the levels of free amino nitrogen (FAN) or S-Methylmethionine (SMM), the precursor for DMS, or any number of other compounds that will change the malt. As we learned in the first part of this series, maltsters can reduce SMM by kilning the malt longer—but of course, that adds color. The art of malting is taking the constituent elements of a given barley variety and making choices—adjusting the biochemical levers—that will give a brewer the malt that works best in the malthouse. Those choices also affect the way the barley variety expresses itself, in just the way a mash choice affects malt expression.
Finally, Campbell and Matt discussed some of the larger issues in malt production, and these last quotes are illuminating. First, the two addressed the question of how barley varieties get selected for malting barley. Campbell begins:
“Anybody can grow any barley they want. Matt and I could go to the seed distributor and pick out what we like, but it doesn’t mean anyone will buy it. Most barley is grown under contract and generally the AMBA (American Malting Barley Association) maintains a list of recommended varieties. It’s a guideline of what people are going to want to contract.”
Then Matt describes how those varieties are selected by farmers, who must balance the desire for large yield with the barley characteristics brewers prize.
“There's a relationship between yield at the farm and the amount of protein. So if you really want to have a highly successful crop in terms of a yield perspective at your farm, you're going to put a lot of nitrogen on there. Well, that nitrogen is the backbone of protein. So, if you want to bump your yield at the farm, you're going to put more fertilizer in the form of nitrogen on your field. Barley producers have a tremendous amount of pride when they get selected for malt. Like, it's a big deal for them. So they want to do what's right, but they also are business people.”
“We've got to make sure we're recommending the right barley varieties for them, for their area, for their unique growing climate, the microclimate in their area. We've got to make sure that we're pricing it correctly, and that may include spending a little bit more on barley with a lower protein spec. Because in that case, we're sort of paying the producer: ‘hey, we know you're gonna grow a little bit less, so we'll give you a few more bucks.’ A lot of this comes down to these multi-generational relationships that we have with barley producers. And working with barley producers to really produce the right material for us to start from. Right? 'Cause everything rolls downhill. And so it starts with the barley, to the malt, to the beer.”
Finally, Cambell adds this, which is quite a bit different from hops:
“Barley is a public-sector crop. There’s very little private money in it. We’re also a specialty crop. There’s a lot smaller volume demand. People are pushing 200 bushels an acre on corn and the highest we get on barley in the US is 100.”
This in no way exhausts the discussion of malt. One of the most important factors is distribution. Barley is heavy and bulky, and shipping it from the Canadian prairie, or even the Washington Palouse, is complex and expensive. But that’s a topic for another day. Today we are content knowing the answer to the question of whether barley variety or malting process is the prime driver of malt flavor. It’s sort of the wrong way to frame the question. Ultimately, you can’t separate barley variety from the process—it is part of the process because it dictates how processing unfolds—and that process doesn’t entirely stop when the maltster packages it up for sale, but continues on into the brewhouse.
Fascinating stuff!