What is underlet mashing?

Another little video prompted by a viewer request. I explain underlet mashing, a favourite technique of English brewers for more than a century. 

 

Mashing scheme of X/MS 6th July 1960

Just about done with Youngs beers in 1960. We conclude with the mashing scheme. Always one of my favourites. 

It’s a rather typical London scheme, featuring an initial infusion, followed by an underlet. The process concluding with a couple of sparges. Nothing at all unusual about that. It’s much the same as you’d find at other breweries in the capital

A further 80 barrels of liquor were added to the first copper before the boil. Giving a total pre-boil volume of 350 barrels. The post-boil volume was 267 barrels. The first copper had an extended boil of three hours to hit the required gravity of 1041º for MS.

Mashing scheme of X/MS 6th July 1960
action	barrels	strike heat	tap heat
mash	64	157º F	145º F
underlet	10	165º F
sparge 1	26	170º F	149º F
sparge 2	160	155º F	153º F
liquor	10
total	270
Source:
Young's brewing record held at Battersea Library, document number YO/RE/1/29.

 

Mashing scheme of PA/PAB 2nd April 1990

What’s left? Mashing. That’s what’s left. Always a fun topic.

It’s a tricky one for me. I don’t record mashing details in the spreadsheet I transcribe brewing records into. Why not? Because the way mashing is recorded varies so much across breweries. And because it would take lots of columns to fully record. Being a lazy git, I just haven’t bothered.

Meaning that I’ve had to go back to the brewing record to extract the following details. Which come from a PA and PAB parti-gyle. I’ve chosen a Pale Ale brew because that was the most common.

It’s a pretty typical English mashing process. What I call an underlet mash. It kicks off with an initial infusion mash. In this case, 136 barrels at 155º F. This was allowed to stand for 30 minutes and then the underlet took place. 15 barrels at 166º F. Which raised the temperature of the mash by a few degrees.

After the underlet, was a continuous sparge of 199 barrels at 166º F to finish off the process. Fairly simple, especially if compared to a decoction mash. 

Mashing scheme of PA/PAB 2nd April 1990
action	barrels	strike heat	tap heat
mash	136	155º F	144º F
underlet	15	165º F	155º F
sparge	199	165º F	162º F
total	350
Source:
Young's brewing record held at Battersea Library, document number YO/RE/1/59.

 

Beer in the DDR (part 3)

Yes, more slides from my DDR talk.

There's more stuff about the DDR hop industry. Including information about how hops were used. Showing how much hop extract could be used. And the small quantity of aroma hops used. Mostly in the posher types of beer.

Then there's some stuff about mashing. Fun fact: the DDR Helles mashing scheme is very similar to how Budweiser was brewed in the 1990s. Both have a rice cereal mash that is used as a decoction. How odd is that?

  

1960s Hydroautomatic Brewhouse (Steinecker)

Even more DDR fun. Sort of. The source is from the DDR, at least.

This time with a more high-tech brewhouse. A two-vessel system. Which, if you paid attention to my post on a four-vessel brewhouse, meant that meant the vessels had dual functions. With the mash tun doubling as lauter tun and the mash kettle doubling up as the wort kettle. As in the system illustrated here.*

It's automatic. Or at least, that's what's claimed. With a brewer only needed to keep an eye on it. Sounds dead groovy. Like the decade that spawned it.

As this was a system developed by a firm, Steinecker of Freising, Bavaria, I doubt very much one was ever installed in the DDR. It would have cost way too much hard currency. Unless the Czechs produced a knock-off back in the communist days. (Or the Good Old Days, as I call them. Much to the annoyance of Dolores.)

Hydroautomatic Brewhouse (Steinecker)

(1) Malt Steeping Vessel
(2) Twin-Roll Mill for Wet Milling
(3) Mash and Lauter Tun
(4) Mash and Wort Kettle
(5) Hop Filter
(0) Control Panel
(7) Sight Window with Liquid Level Indicator
(8) Cutting Unit
(9) Propeller
(10) Hop Feeding Device
(11) Exhaust with Fan
"Technologie Brauer und Mälzer" by Wolfgang Kunze, VEB Fachbuchverlag Leipzig, 2nd edition, 1967, page 265.

* "Technologie Brauer und Mälzer" by Wolfgang Kunze, VEB Fachbuchverlag Leipzig, 2nd edition, 1967, page 264. 

Chapman 14th October 1880 AK mashing scheme

We’ll finish with a look at the mashing scheme.

It’s a rather complicated one. With no fewer than seven operations.

Things kick off with an infusion. Followed by an underlet. All pretty standard stuff. Then there’s something simply described as “O” in the brewing record. My guess is that it means “overlet”. That is, adding hot water to the top of the mash, rather than the bottom, as in an underlet.

There’s then the first sparge, which is followed by a second mash. Which is somewhat warmer than the first. Though the strike heat is lower. The process ended with more sparging.

As there are no column headers for the mashing details, it’s impossible to know whether the rightmost temperatures are initial heats or tap heats. I’m inclined to believe the latter. For all, except the initial infusion mash.

Chapman 14th October 1880 AK mashing scheme
operation	barrels	strike heat	initial heat	tap heat
mash 1	10	168º F	143º F
underlet	1	173º F
overlet	1	173º F
sparge 1	9	176º F		150.5º F
mash 2	3	160º F		150º F
sparge 2	4.5	164º F		158.5º F
sparge 3	4.5	161º F		160º F
Source:
Chapman brewing record.

 

 

DDR Helles Vollbier decoction mash

I spent a couple of days this week writing a talk about beer in the DDR that I'll be giving in Germany next month. It's been a lot of fun.

Much of the material I already had. But there were a couple of areas I had to research a little. One being mashing. Obviously, Kunze's Technologie Brauer und Mälzer was my source. Where I came acorss something I'd previously missed. A brewing record for a Helles Vollbier.

Including just the sort of thing I love. A really detailed mashing record. It's a dual decoction. Though the first is a cereal mash doubling as a decoction. Which is fascinating. As a cereal mash with rice is how Budweiser was made during Mitch Steele's time at Anheuser Busch. You can hear him talk about it here:


Of course, Budweiser didn't get a second decoction, like this Helles did.

It's quite a long process. Six hours in all. Then they spent another four hours running off the wort and sparging. No wonder it never become popular in the UK.

DDR Helles Vollbier decoction mash
action	mash tun			mash kettle
	time	hl	º C	time	hl	º C	time taken
mash in 1,000 kg rice and 1,000 kg pilsner malt				0:00 - 0:35	55	50	35
raise to 65º C in 20 min				0:35 - 0:55	55	65	20
rest 10 min				0:55 - 1:05	55	65	10
raise to 78º C in 15 min				1:05 - 1:20	55	78	15
rest 20 min				1:20 - 1:40	55	78	20
raise to boil in 25min (adjunct mash)				1:40 - 2:05	55	100	25
boil 35 min				2:05 - 2:40	55	100	35
mash in 200 kg Munich malt and 1,800 kg pilsner malt at 50º C	1:45 - 2:00	60	50
rest 40 min	2:00 - 2:40	60	50
mix with adjunct mash	2:40 - 3:00	115	64				20
rest 35 min	3:00 - 3:35	115	64				35
pull decoction				3:35 - 3:40	50	64	5
raise to 77º C in 5min				3:40 - 3:45	50	77	5
rest 10 min				3:45 - 3:55	50	77	10
raise to boil in 15 min				3:55 - 4:10	50	100	15
boil 20 min				4:10 - 4:30	50	100	20
raise to 75º C mash out	4:30 - 4:40						10
rest 30 min	4:40 - 5:10						30
raise to 78º C	5:10 - 5:15						5
saccharification rest	5:15 - 6:00						45
						total	360
Source:
Technologie Brauer und Mälzer by Wolfgang Kunze, VEB Fachbuchverlag Leipzig, 2nd edition, 1967, page 212.

 

 

Adnams 2nd June 1913 XX mashing scheme

The final process is the most important one: mashing.

Surprise, surprise – it’s an underlet mash. A process beloved of English brewers both large and small. With the underlet raising the temperature of the mash by a couple of degrees. It’s not recorded in the brewing record, but there would have been a rest of 20 to 30 minutes between the initial infusion and the underlet.

After the underlet, there would have been another stand, probably of around two hours. Then the sparges would have begun. As was usual, the temperature of the water was reduced as the process progressed. 

And that's Adnams done. At least the 1913 iterations of their beers.  I could go back and do an analysis of their 1879 beers as well. Or 1890. 

Anyone interested in that? I could spin another half dozen posts out of that. Or are you totally fed up of Adnams?

Adnams 2nd June 1913 XX mashing scheme
operation	barrels	strike heat	initial heat	final heat
mash	14	160º F	149.5º F
underlet	0.5	200º F		150.5º F
sparge 1	25	165º F	149º F
sparge 2	26.5	160º F		153º F
Source:
Adnams brewing record Book 1 held at the brewery.

 

Fullers X March 10th 1910 mashing scheme

Just one process left. And that’s mashing. In my spreadsheet of details extracted from brewing records I don’t include anything about mashing. Why? Because what breweries recorded varies enormously. And is difficult to summarise in a couple of columns.

Fullers were one of the better breweries when it came to noting down mashing details

It’s pretty much a classic underlet process. Where there’s an initial infusion mash at 149º F, followed by the addition of a smaller quantity of water introduced from below. This raised the temperature by 4º F.

At some point after the underlet “Saccharum Liquor”, that is a sugar solution, was added to the mash. This is rather odd, as sugar was usually added at the boiling stage.

The process was completed by a sparge at 168º F to 168º F.

A majority of English brewers used a method something like this. The ability to perform an underlet mash being the main reason for retaining internal rakes in the mash tun.

Fullers X March 10th 1910 mashing scheme
operation	barrels	strike heat	initial heat	mashed (mins)	stood (mins)	tap heat
mash	97	159º F	149º F	60	30
underlet	21	175º F	153º F			148º F
Saccharum Liquor	19
sparge	169	168º F
		165º F				152º F
Source:
Fullers brewing record held at the brewery.

 

Fremlin BB 1st Oct 1897 mashing scheme

And how were these beers mashed? In a fairly complicated way is the short answer.

It’s fairly typical of mashing practices in England. The process begins with a small amount of hot water to warm the mash tun. This was followed by an infusion mash, with 18 minutes of mashing.

There was then an underlet with a small amount of hotter water. After which the mash was left to stand for almost two hours.

The process ended with four sparges at descending temperatures.

All of Fremlin’s beers were mashed in a similar way. With the exception of Pilsner, which had a decoction mash. 

Fremlin BB 1st Oct 1897 mashing scheme
operation	barrels	strike heat	mash time	stand time	tap heat
heat tun	4	180º F			148º F
mash	43	160º F	18 mins		153º F
underlet	3	180º F		117 mins	158º F
sparge 1	13	175º F
sparge 2	13	170º F
sparge 3	24	165º F
sparge 4	48	160º F
Source:
Fremlin brewing record held at the Kent Archives, document number U3555/2/F/Bx2/1/22.

 

Boddington 2nd Dec 1901 mashing scheme

We’ll finish with mashing. Which was a pretty simple process at Boddington. Much simpler than at most English breweries. Where the minimum was an infusion mash, underlet and a couple of sparges.

Interestingly, the brewing record does include columns for an underlet, which are filled in with just dashes. Presumably, at one time they had used an underlet but had discontinued the practice.

In this example, there’s just a single infusion with a strike heat of 160º F, followed by a rest of two hours. The process was completed with three sparges at descending temperatures. 

Boddington 2nd Dec 1901 mashing scheme
operation	barrels	strike heat	rest	tap heat
mash	70	160º F	2 hours	150º F
sparge 1		168º F
sparge 2		164º F
sparge 3		160º F
Source:
Boddington brewing record held at Manchester Central Library, document number M693/405/125.

 

7th December 1914 Thomas Usher X, PA and PA 60/- mashing scheme

Finally, we come to mashing. Always one of my favourite bits to interpret in brewing records. Not really. They’re a right pain in the bum. As how the details are recorded is very inconsistent.  And often the most important bits – like initial heat – are omitted.

Let’s see what Usher were up to with their mashing in 1914.

It’s a very Scottish method, with just a single mash followed by multiple sparges. While in England about the simplest a mash got was an initial infusion, followed by and underlet, finished off with a couple of sparges. Though some brewers were still performing multiple mashes.

Compared to 1894, there’s an extra sparge. Which is at the surprisingly low temperature of 155º F. I can’t remember ever seeing a sparge below 160º F. 

7th December 1914 Thomas usher X, PA and PA 60/-
action	strike heat	mash heat	tap heat
mash	157º F	150.5º F	149º F
sparge 1	170º F	155º F	158º F
sparge 2	165º F	160º F	158º F
sparge 3	155º F	153º F	159º F
Source:
Thomas Usher brewing record held at the Scottish Brewing Archives, document number TU/6/1/5.

 

1897 Fremlin Pilsener mashing scheme

Fremlin was lightly unusual for a largish regional brewery in brewing a Pilsener. 

Now, I wouldn't call it exactly a 100% authentic Lager. As it was brewed from pale rather than lager malt. They did, however, use Carlsberg yeast. Meaning it was properly bottom-fermented.

There was also authenticity in the mashing scheme, which was a double decoction. In which there were two boils of half the mash. This was a simplification of their mashing scheme from a few years earlier, where there were three boils, each of a third of the mash.

Here are the full details of the process. 

1897 Fremlin Pilsener mashing scheme
barrels	temp.	mash temp.
9	cold
3.5	210º F	95º F
1/2 boiled		135º F
1/2 boiled		165º F
5	170º F
6	170º F
6	170º F
Source:
Fremlin brewing record held at the Kent Archives, document number U3555/2/F/Bx2/1/22.

 

J. C. Jacobsen talking mashing

More from J. C. Jacobsen's letter of 14th April 1869.

Jacobsen senior was keen on finding out more about mashing in the UK and the composition of the worts it generated.

Kogsbølle, as often as he has time to spare, is busy with analyses of the ratio between sugar and gum in the wort. I would be very happy to carry out these analyses with wort of Scotch ale and Burton ale, in order to learn the result of the English mashing and malting in this respect. I suppose that the wort had to be allowed to come here with a suitable addition of alcohol to prevent spoilage along the way, but I will have to discuss that with Kogsbølle. Have I asked you whether you have tried the first wort that runs in the Younger kettle with iodine? Since the temperature is so low during the mashing, one might imagine that there was some unaltered starch in the wort at the beginning.

Kogsbølle, I assume, worked at Carlsberg. I guess you'd have to add quite a bit of alcohol to wort to preserve long enough to get from Edinburgh to Copenhagen. Otherwise, it would inevitably start to ferment, either with yeast or something else. Would it still be possible to analyse the wort ignoring the alcohol? Would the alcohol change the wort at all?

I find the comments about a low mashing temperature at William Younger a bit strange. The temperatures look totally normal to me. Looking at brews from August 1868, these are the temperatures.

Strike heat: 170º F
1st falling heat: 150º F
1st sparge: 190º F
2nd sparge: 185º F
2nd falling heat: 156º F
3rd falling heat: 166º F

The first falling heat is the temperature of the wort after mashing and standing for two hours. Meaning that the initial mashing heat was higher than 150º. Which seems totally normal to me. And I'm sure sufficiently high to convert all the starch after two hours. What sort of mashing temperature was Jacobsen senior expecting.

Let's take a look at what Jacobsen junior did when he returned to Copenhagen and had his own brewery. This was a brew in 1871.

Strike heat: 70º C (158º F)
1st sparge: 80º C (176º F)

That doesn't look any hotter than the mashing at Younger.

Not quite sure what he means here.

It is strange that in England so little or no importance is attached to letting the hop wort stand on the trays and clear itself, for although you get a complete clarification of the hot wort in the hop vat, you still get a not inconsiderable sediment when it cools, which the English run into the fermentation vat. - I do not like this.

By "tray" does he mean cooler? Because I thought that this is exactly why UK breweries kept their coolers even after installing baudelot coolers. On account of the "cooler sludge" that fell out. 
 

J. C. Jacobsen writes about mash efficiency

In this, Jacobsen senior asks his son to make some calculations as to the efficiency of mashing at William Younger.

14 April 1869.
Dear Carl!
It interests me greatly to see that you are busy with the investigation of the extract quantity of the malt in England and that you can have the malt for a brew weighed (by the way, I am very surprised that this does not always take place at Younger. Are they in Burton equally accurate?) From the quantity of the wort I assume that you can have the exact measure stated in the fermentation vessel, for the measure in the kettle is not sufficiently accurate.- It is quite a long time since I have made accurate observations on the ratio between malt and extract, but at that time I found the result to be in the closest agreement with Balling's statement, according to which in practice one can calculate about 56% of the weight of the malt; i.e. When you measure the wort in the fermentation tank after the cooling, calculate the specific gravity of the wort according to the percentage strength (of which you will find a table at Balling) and multiply the weight of the wort thus calculated by the percentage strength. Since the specific gravity of the water (62 Danish #(pound signs) per cubic foot) is given by the highest degree of density of the water at 4 R [5º C], a reduction should actually be made for the difference between the specific gravity of the water at 4 R [5º C] and at 14 R [17.5º C], which is the temperature at which both Balling's and Kaiser's saccharometers are adjusted, but I have not previously taken this reduction into account. When I now, one of the first days, repeat the examination with all possible accuracy, I will also take the aforementioned reduction into account. It will then be seen, when we compare the yield in Edinburgh and at Carlsberg, whether the English method of mashing delivers an equally large yield as the Bavarian, which I do not quite believe. However, it must be taken into account that the English malt of good Scottish barley is certainly more floury than the Danish and should therefore give a greater yield even of equal weight. Nous verrons!

The bit about weighing the malt is interesting. It sounds like Younger were using volume quarters. Which wouldn't necessarily weigh 336 lbs. Meaning that the brewing record wouldn't necessarily record the exact weight of malt used. Just the volume.

56% of the weight of the malt seems like an awfully high figure. 90 lbs of extract per quarter of malt is about the best you could expect. Which is only around 26% of the weight of the malt. Am I missing something?'

By Bavarian method, I assume that he means a triple decoction. I, too, would love to know how the efficiency of the two methods of mashing compares. Though the superior quality of UK malt might have muddied the comparison. AS Jacobsen himself remarks.

With me, as you know, a part of the last sparge goes into the next mashing as mash water, but since this is repeated in an equal amount throughout the entire cycle of all mashings, it has no influence on the result. I assume the same is the case with Younger. 

That sounds like a return wort to me. Not sure if Younger did that or not, as it isn't mentioned in the brewing records. But it was fairly standard practice. The big London brewers certainly did it.

I would not advise you to concern yourself with microscopic examinations at the present time. They require, first of all, long preparation and practice just to be able to see correctly, and would also require a longer study of the later investigations of Pasteur and others, which are partly found scattered in various Annals, etc. - If you do not have a microscope at your disposal like mine, which magnifies with perfect clarity 1500 times, linearly, you would not be able to see anything with certainty. I have been busy with other things for some time, but I now have various samples ready, which I am going to analyze microscopically. 

1869 was quite an early date for having a microscope in a brewery. I seem to recall that Whitbread only invested in one in the 1870s. And they were ahead of the game in the UK. 1500 times magnification sounds pretty impressive. And must have been an expensive instrument.

 

Even more from J. C. Jacobsen

More from J. C. Jacobsen's letter of 22nd March 1869. this time discussing mashing and malting.

It is not my opinion, however, that you should interrupt the regular presentation of the process at Younger, which you have today begun unless there was something very strange to mention anticipando.- The small mashing machines interest me very much but I have not easily detached myself from the idea that a continued processing of the mashing in the vessel must contribute to the formation of sugars penetrating better into the interior of the small grains, of which the crushed malt partly consists. Incidentally, is the malt not crushed into flour much by the arrangement of the rolling mill, that one roller alone is driven around and the other is dragged along by the friction? and is not the malt grist heated up greatly thereby? Does the wort run off easily and clearly?

Not sure what he means by a small mashing machine. I initially though of a Steel's masher. But that wasn't something that continued after the water and grains entered the mash tun.

I doubt very much that the malt was crushed to flour. That isn't how UK brewers wanted the malt to be in the mash tun.

As for the arrangement of the mash vats in a room by themselves, and the boilers in another, this is very commendable when the boilers are to be open; but with me, where the boilers are closed steam-tight, it is not necessary. And since I have this year put a cover over the hop-strainer - which can be easily raised by a counterweight - there is no steam to be seen in my brewery and it can be kept as white and clean as a living room. You know that both my boilers are now heated by steam in an envelope with only 5-6 (pound signs) pressure per square inch. Do they not use steam boiling in England? I am extremely satisfied with it and think that my beer on the whole approaches very closely to Vienna beer when it has the proper age.

It was fairly common to have the mash tuns and kettles in different rooms in UK breweries. Well, at least the larger ones. Why was Jacobsen so against steam in his brewery? And yes, many brewers did use steam for boiling.

Finally today, barley and malting.

I would like to make a soak (Støb) or two of the best Scottish barley; if it is not too late. Do you think that you could buy 40 or 80 quarters of this barley (according to your sample no. 1) from Theilmann or Stegmann and send it here by steamer at the beginning of April, then you are welcome to make this deal. If it cannot be done now, it can also be postponed until the autumn. I have received a beautiful sample of barley from Proprietor Hvidt near Slagelse, with whom I spoke the other day about Scottish barley. I will buy a couple of soaks (Støb) from him and will send you a sample of the barley so that you can show your Scottish brewers beautiful Danish barley. It is not as round, tender, as the Scottish and far from the heaviest barley that I have received this year. But even my heaviest barley of 118-120 pounds of Dutch has not had the tender form as the Scottish - probably Chevalier barley and there are a few grains in it that have become shell-ripened by the sun. Hvidt said, by the way, that there were only a few places on Zealand by the coast and on the smaller islands where the heavy, Scottish barley could retain its character. Further inland, as with him, it changed immediately and became more long-like.-

It sounds like Jacobsen is quite impressed with Scottish barley. It's worth noting that, at this time, William Younger used large quantities of "foreign" barley in addition to Scottish. The brewing records don't specify exactly where this foreign barley came from. Most likely origins were Chile, California and the Middle East.