Tag Archives: Beer blogs
Here’s an interesting book pointed out to me from a reader, thank’s Peter! It’s called The Theory and Practice of Malting and Brewing. By a Practical Brewer by William Creech You can read it here. The great thing about it is that it was published in 1793, a time that predates the use of Black Patent malt in 1817 (which would eventually replace diastatic brown malt) and it’s also a time where thermometers were used to record temperatures in Farenheit. The Farenheit scale was first introduced in 1724 so it is between these two dates that we can find books published about brewing that include temperatures used in the process of making malt and beer in a more pre-industrial era and by that I mean this predates the mechanization and increased scale of malting. So we get some very useful descriptions of malting and brewing practices that serve as a window into the past. What’s amazing about this book is all of the unique descriptions about brewing practices, things like adding the hops before the boil pg. 37 for a perceptible improvement in flavour. Hmmm gotta try that. Here’s a link to an article on first wort hopping.
There is also mention of using fresh hops for small beer on page 66. But more importantly, this is the first time I’ve seen mention of different colours of brown malt. They are referred to as Brown, Middling Brown, and High Brown. What?! This suggests that malt colour and therefore beer was not as inconsistent as one (being me) might have assumed. And if you’re into brewing historical beers check out the recipes included on page 60-72.
10 lbs Rye at 12.6% moisture steeped to 42%
Steeped 8 hrs + 8 hr air rest + another 4 hr steep (target steep weight 15 lbs) 12° C (53.6°F).
Germinated at 16° C (60.8°F ) for 6 days 1 additional day at 21° C (69.8 ° F). Acrospires 1/2 length of grain.
Kilning for Pale:
24 hrs 37-43° C (98.6-109.4° F) (malt temperature)
8 hrs. at 60° C (140° F)
1 hr. 175° F (79.4° C)
1 hr. 180° F (82.2° C)
2 hrs. 185° F (85° C)
1 lb. green malt stewed at 158° F (70° C) (malt temp) for 2 hr (recommend 3 hrs)
Cover removed 2 hrs. at 200° F (93.3° C) to dry.
30 min. at 250° F (121° C)
Chocolate: Pale malt roasted at 400° F (204.4° C) for 40 min.
1 hr at 109° F (42.8° C) pH adjusted with acid malt to 5.1 – Recommend 2 hrs.
45 min. at 150° F (65.6° C) pH adjusted to 5.3
Pre-boil grav. 1.037
A.B.V. 4.78 %
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
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 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 #3 Blown Malt Same steep
- 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%
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 .
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.
I really did have high hopes for malting oats. I like oats, I eat them for breakfast. I also like putting them in beer, in their raw state or toasted. So I’m very disappointed in this grassy, green corn husk flavour that I’m getting as soon as the oats germinate. This experiment has at least proven that the flavour is coming from the oats and not the husk as I previously suspected. I’m not going to give up on oats completely just yet, I’d like to try a few more things with them, like a caramel for example but as a base malt it’s not a grain I’d recommend. If you’re curious, my process went as follows:
- Steeped for 8 hours at 10C in filtered water to reach a 40.6% moisture content. Hulled oats absorb water very fast.
- Germinated at 16 C for 10 days spraying with water once a day after day 5.
- Kilned for 12 hours at 30-35C with a fan on
- Then 8 hours at 50-55C without the fan (my hot-plate stays on the same setting)
- Cured in my oven starting at 170, 180,190,200F for one hour each.
Ok, mind blown, and I don’t know how I’ve missed this key piece of information. Sometimes I feel like the world of malting is shrouded in so much mystery that you have to be a detective to figure it out. The data in the Scotch Bigg Report provided the biggest piece of the puzzle that was missing for me: that long germination times are only possible with un-aerated steeps. The report gives us actual recorded steep times, which are shockingly long 40-118 hours. What may be even more important was the observation in the report that some maltsters only changed their steep water once or twice and some not at all. But how is this possible? Most texts I’ve read state that the grain will die if submerged for over 24 hours, I’ve told people this myself (my apologies). In fact, I believe it’s only been in the last 150 years that aeration has been used in the steeping process – but I’ll have to do some further investigating to confirm this. In part one of this project, I do a side by side comparison of malt steeped with air rests and malt steeped for 72 hours without. Results in a nutshell: the un-aerated tastes better, but I haven’t brewed with them yet, that’s part two. One factor that may skew the comparison is that I malted these barley samples at the same temperature, which was lower than I would normally malt aerated barley – this may have affected the flavour of the aerated malt. This will be addressed in part three – how does historically malted barley compare with modern malt (malted at warmer temperatures – 15C, 59F)
The Barley and Scotch Bigg Report of 1806 and the influence of a long un-aerated steep on germination time
I recently came across a significant study about brewing and malting that was written in 1806 and it is fascinating. It’s entitled: Report of the Experiments made, by the Direction of the Honourable Board of Excise in Scotland to ascertain the relative Qualities of Malt made from Barley and Scotch Bigg. You can read it here on page 9 (press “preview book”) I am not a beer historian but I believe this is one of the first large-scale surveys conducted for the brewing industry using scientific methods in England. In 1806 Thomas Thomson, along with authors Hope and Coventry conducted a series of experiments comparing the qualities of Barley to that of Scottish Bigg in order to reduce the tax on Bigg since it was thought to make a lower quality malt for brewing and distilling. Bigg is another name for Bere or Bear, an old variety of six-row barley believed to have been introduced to Britain by the Vikings in the 8th or 9th century. It grows faster than barley so it can be sown later and harvested earlier and is ideal for climates with a short growing season. Their findings were published in a report presented to the House of Commons. They concluded that Bigg was 8-14% less productive than English Barley (depending on which author you asked) and proposed that the tax on Brigg should be reduced by one-third. Their survey was very comprehensive collecting the data from malting, brewing and distilling about 36,000 lbs. of English barley, 41,000 lbs. of Scottish barley and 55,500 lbs. of Scottish Bigg. This became a publication that would be referred to for years to come. You can find sections of the report quoted directly 40 years later in The Scottish Ale Brewer and Practical Maltster pg.208 by W.H. Roberts in 1846. By the way, it was Thomas Thomson who devised an accurate hydrometer for this study which was specific for brewing and distilling called the Allan’s Saccharometer.
Of course what I found the most interesting is the section on malting. This is the earliest accurate written survey (in English) that I’m aware of with steep times, moisture content, germination temperature, kilning times and malt temperatures in actual malthouses. I must say the numbers are pretty surprising, like the 20 day germination times and the rather low kilning temperatures. By having this data we’re getting an insight into the brewing and malting methods of the time. For example, the practice described in the report for judging if barley has been steeped enough was to squeeze a grain end to end, if it was soft enough to be crushed then it was deemed to have enough moisture for germination. (This method is also described in the London and Country Brewer of 1736.) But the report also details the weight increase after steeping of each sample (pg 23) and using these numbers we can figure out the moisture contents which, low and behold, were the same ranges of moisture contents used today, 39%-46%. That’s a pretty good “rule of thumb”. We don’t know the initial moisture content of all the barley used in the report but one sample was dried out and according to the weights given had a moisture content of 12.5 %. This is the figure I used in the calculation since any barley that’s properly dried and meant to last in storage would have had a moisture content under 14% so it’s likely a good average number. I think I’ll try this method on my next batch of malt and compare it to my calculated moisture contents.
Even though moisture contents were the same, steep times were very long ranging from 44 hours to 116 hours with the averages being 81 hours for English barley, 76 hours for Scottish barley and 71.5 hours for Bigg. Maltsters were actually required to steep not less than 40 hours by law otherwise they would be fined. The report does mention water changes occurring on pg 20. “Some Maltmen change the water once or twice, while the grain is in the steep, others not at all” I was curious to know what effects such a long steep has on germination and how this does not kill the grain? I found my answer in Malting and Brewing Science pg 48 (Hough, Briggs,Stevens 1971) ” The traditional English practice of long steeps without aeration tends to stifle the grain, and is said to hold back “bolters” so producing more even germination on the floor. As already noted prolonged steeping induces in barley a condition similar to water sensitivity.” Water sensitivity is a condition where the barley will not germinate while there is a surface film of moisture on the grain. This explains why with this method chitting occurs so late, after 4 days according to the report ! When using air rests in the steep regimen chitting often begins before steeping is finished leading to a rapid uptake of water. In describing highly aerated steeping Hough, Briggs, and Stevens state ” Such extreme aeration is probably too costly to use as a routine measure. Particularaly in floor malting, the vigorous growth, with the production of heat, is liable to get out of control, leading to high malting losses…”
Since the germination starts so late with the traditional method it’s safe to assume that the grain will be drier while it is growing thus slowing things down even more. I always wondered why I could not replicate these long germination times using commercial steeping schedules. Every time I tried, my barley would be on the verge of bolting on day 7. As to the wide ranges of times in the report, a major factor in the rate of absorption of water is temperature as well as variety and quality of barley. Also the fact that these samples were carried out by different maltsters could explain some of the variance as well, according to Thomson “They seem to be regulated not so much by any determinate plan, as by custom, or perhaps, in some cases, by caprice.”
On Germination: The times from when the barley was cast onto the floor from the steep tank to the time it was deemed ready ranged from 12 days to 20 for brewing. Shorter times of 8 and 10 days were for distillation. The average for brewing was 14 days for the good quality barley. As mentioned the growth of the acrospire described in the report and in other historical texts was much slower. On page 30 there is a description of acrospires usually reaching only half the length of the grain on days 7-9. It has been my experience that acrospires are at this length after 3-4 days, this makes sense given the extra 4 days required to chit. One way malt is judged to be modified is when the starch turns into a smooth chalky paste, which today happens on day 5-8 (for a pale malt) depending on temperature and barley variety. The same is true for traditional malt and usually occurs when the acrospire is 4/5ths the length of the grain. There is a good description of determining the modification of traditional malt in the 1854 Encyclopaedia Brittanica on Brewing pg 322 which describes the malt undergoing two stages of apparent modification, the “first free” occuring on day 9 – 10 where the grain will feel chalky. At this stage the malt will produce “tolerable” beer. Then the grain hardens once again for another few days until the acrospire has reached 4/5ths the length of the grain usually happening on day 14. It also mentions English germination times averaging 14 days at 62 F and in Scotland 16-20 days at 55 F.
Another highlight of this report are the kiln temperatures, but I’ll save that one for another post.
Have fun reading these links and jumping down this rabbit hole!