Blown vs. Brown malt

Blown malt left, Brown #1 on right

Diastatic brown malt is a dark malt kilned over a fire fueled with coal, wood or straw which has enough diastatic power to convert itself. Made during a time before the widespread use of thermometers and hydrometers the colours and level of diastatic power would have varied between maltsters. An essential source of information on malts of this time comes from the London and Country Brewer by William Ellis published in 1736.

Times for kilning malts is described as being either 4, 6 or 12 hours with the “pale sort” requiring “more leisure and less fire than the amber or brown sorts”  But is it really that simple?

In my previous attempts to make diastatic brown malt a couple of years ago I didn’t think I was successful in answering the question that has been bugging me since the first time I read the London and Country Brewer and that is; how was malt dried in 4 hours with high heat, able to maintain some diastatic power, since enzymes are destroyed very rapidly over 221°F.

Modern brown malt is kilned at a high temperature, 350°F from it’s green stage, right after germination. It will not have any diastatic power.

We do know that brown malt did not have the same diastatic power as pale from the description of kilning brown malt.   “…is often crusted and burnt, that the farinous part losses a great deal of it’s essential Salts and vital Property, which frequently deceives it’s ignorant brewer, that hopes to draw as much Drink from a quarter of this, as he does from pale or amber sorts” (pg.14). What we don’t know are the kilning temperatures.

Some 70 years after this publication a study of brewing industry practices was carried out to determine if Bere barley grown in Scotland should be taxed at the same rate as English barley. The Scotch Bigg Report (Thomas, Coventry and Hope)  presented to the British Parliament in 1806 contains some of the earliest empirical data on brewing and malting collected on a large scale and includes kilning temperatures. This report also pre-dates the development of Black Patent malt (1817). Malts were still referred to at this time as either pale, amber and brown. What I found very surprising in this report is that a temperature of 170°F is given for brown malt which is the same curing temperature for pale malt.  “Malt may be made brown at a lower temperature for it is not so much the temperature, as the suddenness with which it raised, while the malt is still moist, which alters the colour.” Pg. 33 However, they also recorded some maltsters kilning at temperatures of 186°F and suspected some kilned as high as 212°F.

So how does it get dark?   With Munich malt temperatures are raised while there is 20-25% moisture in the malt causing a partial caramelization and it is more highly modified which encourages melanoidin formation upon kilning making a darker malt. It’s also kilned at a higher temperature as well but even Aromatic malt is not as dark as I would imagine a porter being at the time. In my experiments trying to make brumalt I somewhat accidentally achieved a very dark malt by stewing the malt in the proteolytic temperature range of 44-59°C or 113-138°F. So I looked for some clues to see if there was something in the older methods of malting that would promote more Maillard reactions, perhaps if using traditional methods the malt would darken to a greater degree.

One major difference between malting today and back then is the use of continuous un-aerated steeping. In another blog post I tested the theory of un-aerated steeping and it’s effect on slowing the growth of barley and it certainly does, The reason germination times were so long is because of this and to some degree the cooler temperatures. Aerated steeping is a relatively new development (150 years) in the malting industry and was utilized successfully or more consistently due to the development of pneumatic malting. This subject is probably worthy of a book so I’ll stop right here. So in order to mimic the old malting methods I would need to use a continuous steep. There is a theory that because a continuous steep delays chitting that the barley absorbs water more consistently. With aerated steeps the grain usually starts to chit before the last steep. This may cause water to absorb faster at the embryo end as opposed to along the entire length of the endosperm, so the same amount of water may be absorbed but with one end being slightly drier and therefore may affect modification. Chitting during steeping can also cause over steeping which can lead to uncontrolled growth and high malting loss. (Briggs Malts and Malting p.123)

One clue to another difference is in the London and Country Brewer with the mention of a couching phase at the end of germination; “When it is at this degree and fit for the Kiln, (wilted or when “the Root begins to be dead”) it is often practised to put it into a Heap and let it lye twelve Hours before it is turned, to heat and mellow, which will much improve the malt if it is done with moderation and after that time it must be turned every 6 hours during twenty-four.” This is actually very similar to the method used to make Brumalt or Melanoidin malt. The malt is covered and allowed to heat up to 50°C 122°F for 36 hours, only it is not turned and the carbon dioxide eventually stops the growth, but the effect is the formation of reducing sugars and amino acids. Interestingly I found this description in Brewing and Distillation by Thomas and Stewart 1848 “It was formerly the custom in Scotland to pile up the whole grain into a pretty thick heap, and allow it to remain for some time. The consequence is the evolution of a very considerable heat, while at the same time the malt becomes exceedingly sweet.” They go on to say that this is no longer practiced because of malting loss and that “the very same change takes place afterwards in the mash tun, without any loss whatsoever.” 

Lastly, I recently bought a copy of La Practique du Maltage Lucien Levy 1898 and there is a kilning schedule for “Malt Anglais” which states. “It rises as fast as possible to 50 ° (malt temperature and not air). We stay there for about twelve hours.” (Translated from French) It then goes up to 60 for another 12 hours. Interesting! lots of time for proteolytic enzyme activity here especially if it raised to 50° with a high moisture content. However this is not mentioned in the Scotch Bigg report but it does say that kilning takes anywhere from 40-80 hours and that the starting temperature is usually the same as body temperature which is 37°C. With such long kilnings it wouldn’t surprise me that the malt would spend a considerable amount of that time leading up to 50°C and that there would be a lot of enzyme activity during this initial kilning.

I suspected a “hot couch” and some stewing at 50-60°C would definitely add some colour but would it be enough at a kilning temperature under 212°F This will be malt #1

Just to be sure I also planned to make a traditional malt with the hot couch but without the proteolytic stew and just go straight to 205°F for 4 hours. I know with such a high moisture content going this high right away would be bad for the diastatic power but I was more curious to see what effect this would have on colour. This will be malt #2

Blown malt, malt #3

Blown malt on the left, brown on right

In the London and Country Brewer of 1736 a distinction is made between malt that is “blown” and brown malt.

 On the subject of frames, or the materials used for the kiln floor it states “the Iron and Tyled one, were chiefly Invented for drying of brown Malts and saving of Fuel, for these when they come to be thorough hot will make the Corns crack and jump by the Fierceness of their Heat, so that they will be roasted or scorch’d in a little time, and after they are off the Kiln, to plump the Body of the Corn and make it take the Eye, [ What I believe “take the eye” means is that it will simply look better by increasing in volume. In Wigneys 1823 Philosophical Treatise of Malting and Brewing he describes the effect of  sprinkling as “giving to the malt a plump, fair appearance to the eye…” ] Some will sprinkle Water over it that it may meet with better Market. (Malt was sold by volume) But if such malt is not used quickly, it will slacken and lose it’s Spirits to a great Degree, and perhaps in half a year or less may be taken by the Whools (a small insect) and spoiled: Such hasty dryings or scorchings are also apt to bitter the Malt by burning it’s skin, and therefore these Kilns are not so much used now as formerly” This is a criticism of surfaces that conduct or retain too much heat. What he is describing is “blown malt” although he does not refer to it as such. Corns that “crack and jump” and expand in size will occur when temperatures are high and the moisture inside the grain cannot escape fast enough. 

Most recipes for Blown malt after Black Patent malt comes into use refer to it as simply Brown or Porter malt. All the recipes I’ve read dry the malt  to a certain degree first. In Brewing and Distillation by Thomas Thompson and William Stewart (1848)  “Brown or Porter malt is dried by applying the same heat at first as to pale malt, and after it is half dried, by blowing it (as it is termed) on the kiln. This is done by raising the heat as high as the men who turn it on the kiln can possibly stand. This may be stated at 200° for the first turning, and higher afterwards.”  The same thing is stated 50 years later in La Practique Du Maltage: The brown malt or blown is obtained as follows: We take malt half kilned and we carry it in a second kiln heated with a large fire of oak or beech it is installed in layers of 3-4 centimeters.

What also encourages this popping effect is the shrinkage of the pores of the husk which occurs after the “free drying” stage of kilning which happens at around 23% moisture. So if the temperature is raised very rapidly at this point the steam formed will not be able to escape fast enough and the kernel will pop. I suspect the sprinkling of water can increase the malt temperature faster by adding steam to the malt bed. I decided not to try sprinkling water on mine. This time I just wanted to try drying the malt down below 30% and subjecting it to a high heat, above 212°F. I put it in the oven at 350°F which may have been overkill but it sure popped! It sounded sort of like popcorn when it really got going after 20 minutes at this temperature.

Malt #1 Hot couch and 21 hr. stew+ 4 hours at 205-210F

• Malt #1 Continuous steep until 44% changed water twice
• 8 day germination. Malt temp. between 11-13°C 52-55°F
• Hot couch 36 hours in an open cooler to mimic a larger amount of malt. Temp. reached 39°C Turned after 12 hours then every 6.
• 21 hours kilned lightly covered, closed vents, no fan at around 50°C
• Moisture now at 28%
• Kilned for 2 hours at 205*F
• 2 hours at 210°F

 

• Malt #2 Continuous steep until 44%
• 8 day germination 11-13°C 52-55°F
• Hot couch 36 hours temp. reached 39°C 102°F
• kilned for 4 hours at 205°F moisture at 14%
• kilned another hour and a half  at 205°F moisture down to 6% Colour was light!
• kilned another 2 and a half hours at 210°F (8 hours total kilning) Colour now at around 30L

Malt #2 Hot couch, no stew and 8 hrs. at 205-210.

• Malt #3 Blown Malt Same steep
  

  Blown malt #3

• same germination
• same hot couch
• same limited stewing at 50°C 122°F as malt #1
• Moisture at 28%
• Kilned for 40 minutes at 350°F
• Moisture below 5%

Blown malt #3

 

 

Observations: When comparing the Blown malt to malt #1 the colour is almost the same. I was really excited to see how dark #1 got. Much darker than my previous attempts at Brown malt. Because malt #2 remained light, even after 8 hours kilning,  it’s safe to attribute the darkness in colour in malt #1 to the limited stewing phase at 50°C. I ran them all through a mini-mash at 152°F pH adjusted to 5.2 (or as close as possible with a little baking soda or some acid malt) for one hour. I was not using the standardized congress mash, instead, I was using a scaled down version as if I were brewing a 5 gallon batch with 10lb of malt only I was using 4 oz of malt. The math may have gone a little sideways but as long as it was the same for each I thought it would make an interesting comparison.  Of course #1 had the highest brix at 9° and the blown had the lowest at 7°. I was pretty surprised to see that Malt #2 had some diastatic power at 8°. As a control I made another mini-mash the same way with a pale malt and it also scored a 9°.

Mash #2 which did not have the initial lower temperature kilning remained a gloopy mass and the mash did not separate from the wort. This was not surprising as the beta glucans had not been broken down which may show the importance of the enzyme activity during kilning below 50°C 122°F or more specifically in the 37-45°C 98-113°F range .

Malt #2 after mashing notice the lack of separation of wort.

Malt #2 after 5 1/2 hours kilning at 205°F and still light.

 

The flavour of the Blown was bitter and slightly charry like a roasted malt. The interior of some of the kernals was charred while the exterior looked a nice light brown with some darker areas. Malt #1 tasted great nice and malty. As for volume the malt was divided by weight before kilning. After kilning Malt #1 measured 4 1/2 cups. The Blown was 5 cups, a difference of 10% Perhaps it would have been more had I sprayed some water on it during kilning.

 

I know I’ll get a lot of people questioning my methods here they’re not the most scientific, but I think it answered some questions in my mind about the effects of using a proteolytic stewing (or a slow kilning) phase. Also I think it’s safe to say that by omitting any initial drying or even withering phase the London and Country Brewer article has an oversimplified version of the kilning process. That may have been obvious to a lot of people but I know it has caused a lot of debate amongst others.

What I’d like to try is kilning at a lower temperature and raising the temperature when the moisture content is lower around 20%. I’ also like to try making a blown malt at 200-250°F which is where I observed some popping happening during my first attempts at brown malt as I think this may be more historically accurate. But first I think I’ll make a much larger batch for a more historically accurate porter and perhaps this time I’ll get to play with some fire!

Many thanks to Melanie and Andrew at McInnes Farms for supplying me with a big sack of Newdale barley grown 10 minutes away from where I live. These experiments and many more to come will be done with this barley.

Mini mashing

Mini sparge

 

Sweet brown bread malt

I made this unique tasting malt while trying to make a Brumalt style malt from store-bought Pale malt. I can’t think of another name for it because brown bread with honey on it is what it tastes like. Brumalt starts out differently than pale malt so making it from a Pale is not actually possible. It’s steeped to a higher moisture content, germinated at warmer temperatures and has a stewing phase before kilning, but I was curious to find out what would happen if I soaked a pale malt till it had about a 50% moisture content and ran it through a kilning schedule that’s similar with an emphasis on activating the proteolytic enzymes. A good way to soak pale malt is to add just enough water so that it will be around 50% after absorbing it. This way no enzymes or sugars get washed down the sink. Make sure to keep it cool.  After the malt absorbed almost all of the water I drained the excess and then  stewed it for 36 hours on a tray covered with tin foil (8 hours 30-40C then 24 hours 40-50C). I then dried it at low temperatures 35-50C on a screen with a fan on for the first seven hours then off for the next 15.  After 22 hours of drying it was down to its original weight so I cured it for 3 hours at 190F.  What I noticed when using pale malt is that it dries faster than regular malt. Since it has been kilned once already the outer layers are now friable and allow an easier passage of moisture. Likewise, Pale malt also absorbs water faster than barley so it takes one steep of 12-14 hours to attain about a 50% moisture content or 24 hours using the absorption method.

 

Malting Buckwheat

 

Here’s another gluten free alternative for brewing that doesn’t have the problems associated with malting Sorghum. However, I would only recommend using small amounts in your recipe because the beer I made using 100% buckwheat malt is only drinkable if you like sesame flavoured cough syrup. I actually don’t mind the flavour but it’s the viscosity that I just can’t get used to which seems to get thicker the colder it is. The carbonation helps a little bit but I have yet to finish a pint. The Sorghum beer was much better. Perhaps a thinner mash during the beta-glucan rest and resting for longer, may have helped. Anyway here’s what I did:

The Buckwheat that I bought was about $50 for a 25lb bag. Unfortunately it came all the way from China, so much for going local. There are a lot of reasons for the decline of the buckwheat market here in Canada which are explained in this article  in Grainews from 2015. Basically China has lower production costs, is closer to larger markets like Japan and there are more lucrative crops for Canadian farmers like canola and soybeans.

The procedure that I’m loosely following is from a few articles which you can find in Information on Malting section of my blog. In one of these articles they compare the results of 3 different steep times and makes the claim that an ideal procedure which would yield the best balance between the high enzyme potential and low malting loss would be starting with a moisture content of  around 40% steeped at 10C for 13 hours and germinated at 15C for 4 days or 96 hours with the average length of the root would being 17 mm. According to another article by Wijngaard enzyme production does not increase after 4 days.

But is it ever this easy? Heck no! The temperature of my garage at steeping was 13C, I also used cold filtered water. I was surprised to see how fast the grain absorbed water, within a couple of hours the volume almost doubled. At the 6 hour mark I decided to weigh one of the 3 trays. I had started wih 5 lbs of grain in each one. I poured out the steep water which was now a mucus like slime –  wasn’t expecting that!

Not really sure what the slime is, starch perhaps?  Apparently, it’s normal. I rinsed the grain a number of times with cold water to wash off the slime but it still seemed to hold a lot of surface moisture. My weight was way above my target so, to get a more accurate weight I decided to dry the surface moisture by putting it in my kiln with the fan on at 20C. I did this for 3 hours, until it felt damp but not wet. The new weight was much lower and at 7 lbs and 2 oz I was 2oz under my target weight. So this batch had a 39% moisture content. I had also drained off the other two trays and rinsed them as well but I decided to let them dry naturally and absorb some of the surface moisture. In doing this I ended up with one tray being 44% and the other 46%. The 46% batch was not drained as well and absorbed the extra water.  At least this way I’d get to see for myself how the moisture contents affect growth, and they really do. Even on day two there was a huge difference with the higher moisture buckwheat growing much faster than the 39% batch.

Because buckwheat grows so fast it puts out A LOT of heat. I noticed after 24 hours the higher moisture trays were getting warm up to 22C with the ambient temperature being 15C so I split each of these trays into two trays for each. This worked a little but I would definitely recommend using a tray or container large enough so that you can spread the grain down to only an inch or less in depth. After 48 hours the low moisture tray really took off and the temperature reached 25C! yikes. So I split that one too.

At the end of day 3 growth seemed to stop and the roots withered slightly during the 4th day. Here are the stats at 96 hours.

Moisture       Germination     Root length average

• 39%              82%                 12 mm
• 44%              98%                 17 mm
• 46%              96%                 20 mm

 

It looks like the buckwheat with a 6 hour steep, but properly drained would be ideal. At 96 hours the buckwheat was still warm at around 17 C so I gave it for another 6 hours before kilning it. I kilned it very low, below 40C with the fan on for 18 hours. It was very dry at this point (although I neglected to weigh it). I then turned the fan off and the temperature rose up to 60C for a couple of hours and then I increased the temperature to 170 for 4 hours.

I also made some specialty malts for this beer. The first of which was a caramel buckwheat malt. I took a little over a pound of the high moisture green malt and stewed it at 50C for 3 hours on a tray under tinfoil. Then I raised the temperature to the saccharification range at around 158F for another 3 hours. I then took off the tinfoil cover and let it dry out at 170F in my oven.

Brown buckwheat malt. I then took some of the green malt and roasted it to make a modern brown malt. This had a very unique cinnamon bark flavour to it. I roasted it at 250F for an hour, 300F for 30 minutes and then 350F for 15 minutes.

After kilning the base malt I also thought it would be a good idea to make a darker roasted malt. I roasted about 6 ounces at 400F for 30 minutes to make something close in colour to a chocolate malt. It had a very mild roasted flavour but it didn’t seem to add much colour or flavour to the finished beer so I probably could have made a lot more. Here’s what went in this recipe:

• 11.5 lb Buckwheat malt
• 12 oz Caramel buckwheat malt
• 7 oz. Brown buckwheat malt
• 5 oz Chocolate buckwheat malt

Brewing: According to the article a multistep mash will have better results than a single infusion mash. 15 min. at 95°F,  30 min at 113°F, 1 hour at 149°F and 30 min at 161°F  and mash out at 172°F.  Also, a thin mash produced better results than a normal thicker mash which also helped with lautering. So I kept it simple and used infusions of boiling water to bump up the temperatures  and thin the mash just making sure that when the mash was at 149 the liquor to grist ratio was 4:1. I added one more infusion to get to 161F The inclusion of this temperature in the article kind of confused me, wouldn’t it have been better to rest at 158? I then drew off 7 litres of wort, boiled it then added it back to the mash to reach 172F the final mash out temperature.

Lautering – I don’t want to talk about it. Ok it wasn’t that bad, luckily I used a brewing bag because I had to suspend the bag for about 30 minutes to let the wort drain out. I also took some grain out and put it in a strainer to drain but in hindsight, this wasn’t necessary as it would have eventually drained out of the brew bag. I estimate that maybe a half gallon was still locked up in the spent grain but it just wasn’t draining out, oh well time to move on. The boil was uneventful, thankfully! Because of it’s thick viscosity that seven litres of wort that I drew off during the mash ended up boiling over and making a mess of the stove top so I was worried about another boil over on a larger scale. I was very cautious and watched the temperature closely. When it reached 210F I turned the gas way down and kept stirring. It slowly came to a boil without foaming up.

Fermentation was really fast and pretty violent. At one point the blow-off tube became so plugged that the stopper actually shot off making a loud bang inside my brewing fridge.

O.G. 1.059  F.G. 1.0089  A.B.V.  6.46%

The Beer: Tastes like compost? earthy, with a strong birdseed flavour, throw in some peanuts too. There’s also a pine like grassiness from the hops. which totally does not go with the nutty flavour. I used the hops I picked at the side of the road, which I’m pretty sure are B.C. Goldings. I didn’t do an acid level comparison this year but they seem much more acidic than previous years.

What is hard to get used to is not the flavour but the viscosity. When it’s cold it’s thick like cough syrup. Pretty gross. I think I’ll stick to barley.