Showing posts with label Oatmeal Stout. Show all posts
Showing posts with label Oatmeal Stout. Show all posts

Monday, 10 August 2026

What is Oatmeal Stout?

Another of my little YouTube videos, this time about Oatmeal Stout. Well. Oat Malt Stout, too. 

 

Wednesday, 18 March 2026

Let's Brew Wednesday - 1991 Youngs Oatmeal Stout

A Youngs Oatmeal Stout label featuring a drawing of a ram.
After disappearing sometime in the 1960s, Oatmeal Stout made a comeback in the 1990s. To many people’s surprise.

This beer is quite strong for a post-WW II Stout and is around the gravity of pre-WW II Oatmeal Stouts.

Unlike London Oatmeal Stouts from before the war, where the oats content was minimal, there’s a decent amount here. Maybe even enough to be noticeable. Other than that, the grist is quite simple. Just base pale malt and a bit of roast barley. Along with some Young’s Special Mix, a combination of glucose, molasses and caramel.

There’s not much else to say, really.  Just two types of English hops. Again, with no indication of vintage. And I’ve had to double the quantity to hit the bitterness level recorded in the brewing record. 

1991 Youngs Oatmeal Stout
pale malt 10.00 lb 81.17%
roast barley 0.55 lb 4.46%
flaked oats 0.75 lb 6.09%
glucose 0.75 lb 6.09%
molasses 0.25 lb 2.03%
caramel 2000 SRM 0.02 lb 0.16%
Fuggles 70 min 2.25 oz
Goldings 10 min 1.00 oz
OG 1055
FG 1014
ABV 5.42
Apparent attenuation 74.55%
IBU 31
SRM 18
Mash at 149º F
Sparge at 165º F
Boil time 70 minutes
pitching temp 63º F
Yeast WLP002 English Ale

 



Listen to brewer John Hatch explain how they brewed at Youngs in the 1990s.  

Wednesday, 11 June 2025

Let's Brew Wednesday - 1911 Eldridge Pope Double Stout

An Eldridge Pope Double Stout label featuring a monocled huntsman holding a glass of beer.
Just 3º lower than in 1896 is Eldridge Pope’s other Black Beer, Double Stout. Even though that leaves it under 1060º and not much stronger than a London Porter. Far short of what you’d expect for a Double Stout.

As this was parti-gyled with the Light Tonic Stout, I don’t really have anything to say about the recipe. This was the junior party in the parti-gyle, amounting to 52 barrels compared to LTS’s 94.

Unlike LTS, Double Stout was sold in draught form. Costing the same as Pale Ale: 54 shillings for a 36-gallon barrel.

This does not look like a candidate for extended ageing. I can’t see there being more than a couple of months between racking and consumption. 

1911 Eldridge Pope Double Stout
pale malt 7.50 lb 59.41%
crystal malt 60 L 1.125 lb 8.91%
black malt 0.750 lb 5.94%
oats 1.50 lb 11.88%
No. 2 invert 1.500 lb 11.88%
caramel 1000 SRM 0.25 lb 1.98%
Cluster 120 mins 1.00 oz
Fuggles 60 mins 1.50 oz
Fuggles 30 mins 1.50 oz
OG 1059
FG 1018
ABV 5.42
Apparent attenuation 69.49%
IBU 51
SRM 38
Mash at 150º F
Sparge at 165º F
Boil time 120 minutes
pitching temp 59.5º F
Yeast White Labs WLP099 Super High Gravity


Saturday, 7 June 2025

Let's Brew - 1911 Eldridge Pope Light Tonic Stout

An Eldridge Pope Oat Malt Stout label featuring a monocled huntsman holding a glass of beer.
There’s nothing more typical of the late Victorian and Edwardian period than the new type of low-gravity Stouts. Mostly sold in bottled form. And this is a great example.

Low-gravity is certainly what this beer is. It’s even 5º lower than in 1896. Quite a few changes to the recipe, too. The brown malt has been dropped and in its place is quite a bit of crystal malt. Another addition was a rather considerable quantity of oats. Much more than the usual token amount to allow a beer to be sold as Oatmeal Stout.

There’s also been a change in the sugar. The No. 3 invert has been replaced by DM, or dextro-maltose. I’ve substituted No. 3 invert.

Three types of hops, Kent from the 1908 harvest, along with English and Oregon from 1909. 

1911 Eldridge Pope Light Tonic Stout
pale malt 6.00 lb 58.82%
crystal malt 60 L 1.00 lb 9.80%
black malt 0.625 lb 6.13%
oats 1.25 lb 12.25%
No. 2 invert 1.125 lb 11.03%
caramel 1000 SRM 0.20 lb 1.96%
Cluster 120 mins 0.75 oz
Fuggles 60 mins 1.25 oz
Fuggles 30 mins 1.25 oz
OG 1047
FG 1015
ABV 4.23
Apparent attenuation 68.09%
IBU 44
SRM 33
Mash at 150º F
Sparge at 165º F
Boil time 120 minutes
pitching temp 60º F
Yeast White Labs WLP099 Super High Gravity


Wednesday, 15 November 2023

Let's Brew Wednesday - 1910 Barclay Perkins Oatmeal Stout

In the first decade of the 20th century, Oatmeal Stout became a big thing. The original Oat Stout came from Maclays of Alloa, who tried to patent their invention. Most brewers dodged this by simply using oat malt instead of malted oats.*

It’s a pretty complex grist. Even more complex than it appears from the recipe. As around a third of the base malt was SA malt. Obviously, there are also oats. I think in the form of flakes. But not a huge amount of them. Unlike the roasted malts, which make up more than a third of the total.

The mashing was still going the same way: mash, underlet, mash, sparge, sparge. Still very complex compared to, for example, a typical Scottish process, of a mash and maybe two sparges.

Mash number barrels strike heat mins stood tap heat
mash 1 48 155º F 105  
underlet 8 172º F 30 147º F
mash 2 24 174º F 30 157.5º F
sparge 1 26 170º F   153.5º F
sparge 2 38 165º F   151.5º F

Three types of hop graced the copper: Kent from the 1907 and 1909 harvests and Sussex from 1908.

No ageing for this beer. 

1910 Barclay Perkins Oatmeal Stout
pale malt 5.00 lb 43.37%
brown malt 1.50 lb 13.01%
black malt 1.25 lb 10.84%
amber malt 1.25 lb 10.84%
flaked oats 0.33 lb 2.86%
No. 3 invert sugar 2.00 lb 17.35%
caramel 500 SRM 0.20 lb 1.73%
Fuggles 120 min 1.25 oz
Fuggles 60 min 1.25 oz
Goldings 30 min 1.25 oz
OG 1053
FG 1017
ABV 4.76
Apparent attenuation 67.92%
IBU 48
SRM 45
Mash at 151º F
Sparge at 170º F
Boil time 120 minutes
pitching temp 61º F
Yeast Wyeast 1099 Whitbread Ale

 

* See Martyn's correction in the comments.

This recipe is one of more than 250 in my book "Stout!" Come and her me talk about the history of Stout At Poesiat & Kater on Saturday 18th November , 13:00-14:00.

This is the event page:

https://facebook.com/events/s/the-story-of-london-stout-by-r/304408102440443/

This is the book based on the talk (and much expanded). Get your copy now!



Saturday, 29 July 2023

Let's Brew - 1925 Barclay Perkins Oatmeal Stout

Another beer making a reappearance was Oatmeal Stout. No surprise, as it was a popular kind of beer, at the time

Most brewers just threw a handful of oats into their standard Stout and labelled some of it as Oatmeal Stout. Barclay Perkins took a different approach. They brewed it separately, in a tiny batch (just over 24 barrels). So, did they use more oats? Of course, they didn’t. A mere 30 pounds.

There are a lot of ingredients. A bit of flaked maize here, a little crystal malt there. Roast barley for colour this time. The sugar is described as “Martineau BS”. I would have assumed that meant something like No. 4 invert. But that would make the beer way too dark. No. 3 gets it around the right colour.

Just four steps to the mash. Perhaps because of the small volume they didn’t bother with a second sparge.

Mash number barrels strike heat mash heat mins stood tap heat
mash 1 9 152º F 147º F 30  
underlet 2 183º F 151º F   145.5º F
mash 2 5 172º F   30 153.5º F
sparge 16 172º F     158º F

Only two hop types, both Mid-Kent, one from the 1923 harvest, the other from 1924. Both stored cold.

More Martineau BS was added as primings, raising effective the OG by 2º. I’ve added more No. 3 invert to account for this. 

1925 Barclay Perkins Oatmeal Stout
mild malt 5.50 lb 49.13%
brown malt 0.50 lb 4.47%
amber malt 1.25 lb 11.17%
crystal malt 60L 0.75 lb 6.70%
roast barley 1.00 lb 8.93%
flaked maize 0.50 lb 4.47%
flaked oats 0.02 lb 0.18%
No. 3 invert sugar 1.50 lb 13.40%
caramel 500 SRM 0.175 lb 1.56%
Fuggles 120 min 1.25 oz
Fuggles 60 min 1.25 oz
Fuggles 30 min 1.25 oz
OG 1053
FG 1017.5
ABV 4.70
Apparent attenuation 66.98%
IBU 44
SRM 32
Mash at 151º F
Sparge at 172º F
Boil time 120 minutes
pitching temp 63.5º F
Yeast Wyeast 1099 Whitbread Ale

This recipeis one of 270-odd in my new book on London Stout. Get your copy now!



Wednesday, 24 August 2022

Let's Brew Wednesday - 1914 Hancock Stout

Has Stout followed the trend of the other Hancock beers and had its gravity reduced? Of course, it had. None of their beers were immune. Though it’s only 3.5º lower.

The gravity is not where the big changes are. They are in the recipe. The 1897 version was a simple beer, consisting of just pale, crystal and black malt. Three new ingredients have been added, two of them types of sugar: Durax and oatine. The other was flaked oats.

What does this tell us? Well, obviously, they were selling at least some as Oatmeal Stout. It’s interesting that the style had already made it to the Southwest. The first oat Stout, from Maclay of Alloa, had been brewed less than 20 years earlier.

The sugar content is pretty high, just shy of 30%. Which makes it all the more annoying that neither of them exists any more. I’ve substituted No. 3 for both, but who knows how close that might be. You may want to add extra flaked maize for the oatine.

There were two types of hops, one from Oregon and the other English. No harvest date is given for either.

1914 Hancock Stout
pale malt 5.75 lb 47.92%
crystal malt 60 L 1.50 lb 12.50%
black malt 0.50 lb 4.17%
flaked oats 0.75 lb 6.25%
No. 3 invert sugar 3.50 lb 29.17%
Cluster 120 mins 0.50 oz
Goldings 120 mins 1.00 oz
Goldings 30 mins 1.00 oz
OG 1062
FG 1015
ABV 6.22
Apparent attenuation 75.81%
IBU 34
SRM 32
Mash at 152º F
Sparge at 170º F
Boil time 120 minutes
pitching temp 58º F
Yeast White Labs WLP099 Super High Gravity

Monday, 27 May 2019

Oat Porter

The Free Mash Tun Act opened the door for another ingredient, flaked oats. The first Oatmeal Stout, brewed by Maclay in Alloa in 1890s contained a whacking 30% of malted oats.

Brewers who followed the trend, most likely trying to dodge Maclay’s patent on Oat Malt Stout, usually went for flaked oats. In quantities so small, they could only have been for legal purposes. At no more than 1% of the grist, far too little to have any impact on the character of the beer.

No-one in London set up to brew an Oatmeal Porter. It was simply a side-effect of parti-gyling. As Porter usually shared its grists with the Stouts, there was simply no avoiding it, if you wanted to brew an Oatmeal Stout.

There never seems to have been an attempt to market this by-product. Perhaps because Oat Stout was usually a bottled product. And by this point Porter wasn’t usually bottled. A fact which probably hastened its demise. Stout, for example, managed to survive in bottled form long after draught versions disappeared.

With oats making up less than 1.5% of the grist at Truman, they were pretty typical of London brewers.


Truman Runner grists 1880 - 1909
Year OG lbs hops/ qtr hops lb/brl pale malt brown malt black malt crystal malt oats flaked maize caramel sugar
1880 1056.8 12.8 3.84 44.15% 11.13% 4.45% 40.27%
1890 1058.2 9.1 2.50 66.77% 10.02% 6.01% 17.20%
1895 1057.6 7.1 1.92 65.33% 10.89% 6.82% 16.97%
1899 1058.2 7.3 1.99 56.17% 11.70% 7.83% 10.01% 14.30%
1905 1054.3 5.8 1.35 63.91% 7.58% 5.13% 9.57% 3.19% 10.63%
1909 1058.2 8.2 2.31 67.30% 5.66% 5.41% 5.41% 1.47% 2.60% 4.05% 8.10%
Sources: Truman brewing records held at the London Metropolitan archives, document numbers B/THB/C/082, B/THB/C/092, B/THB/C/096, B/THB/C/102, B/THB/C/108 and B/THB/C/112.

You'll find more information that you'll ever need to know about Porter in my excellent book on the subject:




Saturday, 9 March 2019

Let's Brew - 1939 Whitbread London Stout

There was some variation in the draught beer classes of London beers. Especially when it came to Stout.

For while some breweries had an 8d draught Stout with an OG of over 1050º, others brewed it as a 7d a pint beer, with a gravity of 1047-1048º. Whitbread belonged to the latter group.

For a brewer who had been brewing Porter since the 18th century, London Stout was a surprisingly recent product. It was first brewed just before WW I, in 1910. It immediately become Whitbread’s second most popular beer, only outsold by their Mild, X Ale.

As with their Porter, chocolate malt has been substituted for black malt. No surprise there, as London Stout was parti-gyled with Porter. At least for the moment. Porter wasn’t going to be around for much longer. Not sure why Whitbread moved over to chocolate malt. Their London rivals stuck with either black malt or roasted barley.

The tiny percentage of oats are there so Whitbread could legally sell some of this as Oatmeal Stout. Legally, if not morally, they were in the clear. All a bit of a con really, though. I wonder if anyone ever tried blind tasting the standard Stout and Oatmeal Stout? And did they cost the same?

The hops were the same, obviously, as the Porter with which it was parti-gyled: Mid-Kents from the 1936, 1937 and 1938 crops; Polish from 1938 and “Old Continentals”. A truly cosmopolitan bunch.


1939 Whitbread London Stout
pale malt 7.50 lb 71.98%
brown malt 0.75 lb 7.20%
chocolate malt 0.75 lb 7.20%
flaked oats 0.09 lb 0.86%
No. 3 invert sugar 1.00 lb 9.60%
caramel 1000 SRM 0.33 lb 3.17%
Hallertau 75 mins 0.50 oz
Fuggles 75 mins 0.75 oz
Goldings 30 mins 1.25 oz
OG 1047
FG 1015.5
ABV 4.17
Apparent attenuation 67.02%
IBU 31
SRM 39
Mash at 149º F
Sparge at 170º F
Boil time 75 minutes
pitching temp 62º F
Yeast Wyeast 1099 Whitbread Ale

Wednesday, 24 October 2018

Let's Brew Wednesday - 1966 Maclay Oat Malt Stout

Just when I thought Maclay’s records were as exciting a wet February weekend in Skegness, they throw in something completely different. Not an Oatmeal Stout, but an Oat Malt Stout.

Maclay were the first to brew an Oat Stout, way back in the 1890s. They tried to patent Oat Malt Stout, but other brewers simply used flaked oats and called their beers Oatmeal Stout. It’s weird that the two new types of Stout that appeared 1890 – 1910 both came from small, regional breweries. Oat Stout by Maclay, Milk Stout by Mackeson.

While London brewers threw in a token amount of flaked oats into their Oatmeal Stout, Maclay’s version always contained a considerable proportion of oat malt. In this example, it makes up a full third of the grist.


1966 Maclay Oat Malt Stout
pale malt 3.25 lb 42.15%
black malt 0.67 lb 8.69%
malted oats 2.50 lb 32.43%
No. 3 invert sugar 1.25 lb 16.21%
caramel 5000 SRM 0.04 lb 0.52%
Fuggles 90 mins 0.50 oz
Fuggles 60 mins 0.50 oz
Fuggles 30 mins 0.50 oz
OG 1035
FG 1012
ABV 3.04
Apparent attenuation 65.71%
IBU 21
SRM 34
Mash at 145º F
Sparge at 165º F
Boil time 90 minutes
pitching temp 62º F
Yeast WLP028 Edinburgh Ale

You can find this recipe, along with literally hundreds of others, in my post-WW II British brewing:

http://www.lulu.com/content/paperback-book/austerity/23181344



Thursday, 10 November 2016

Malted wheat and oats

Sorry about this. I never quite finished everything in "Brewing Theory and Practice" about grains. Just got distracted, as usual.

Though in a way it’s a good thing that I was delayed. Because I’ve since got my hands on more brewing records from the 1950’s. Where malts other than from barley do show up.

But I’ll let Jeffery talk first.

“Malted Wheat and Oats
In addition to malt made from various types of barley, both wheat and oats can be malted. The former is difficult to put through the process because the acrospire grows outside the skin of the grain, and thus has no protection. Consequently, the malting of wheat is not a proposition favoured by maltsters. But when properly malted and used in mild ales, it imparts a fullness of flavour to the beer and also provides valuable feeding properties for yeast.”
"Brewing Theory and Practice" by E. J. Jeffery, 1956, pages 132 - 133.

OK, I think I get that. Wheat is difficult to malt, but it fills out Mild Ales nicely. Let’s take a look at actual practice. Flowers, a later Whitbread victim, used wheat in some of their beers. In 1955 they brewed nine different beers of which four received some wheat. But it wasn’t in the Mild Ale or Brown Ale. It was in their bottled Pale Ales. The percentage was pretty small, just 3% or 4% of the grist.

Let’s try another brewery. Shepherd Neame, they also dabbled in wheat. And in 1956 they also brewed nine beers, four of which contained malt. Once again, Mild wasn’t one of them. The four were Abbey Ale (a Strong Ale), Double Brown, Brown Ale and Light Dinner Ale. Interestingly, all bottled beers again. The proportion in the grist was again below 5%.

In the 1960’s, Eldridge Pope had malt wheat flour in pretty well all their grists: Bitter, Old Ale, Mild Ale, Brown Ale and Strong Ale. Only Lager and Stout received none. And when they first brewed Hardy Ale in 1967, that too contained wheat malt flour. Quite a lot of it, at over 10% of the grist.

I can’t make any sense out of that. Two breweries seem to have used it just for bottled beers, the third for just about everything. In the case of the first two, my guess is that the main purpose of using wheat, especially given the small quantities, was head retention. At Eldridge Pope the amounts are too large for that to be the reason. In the case of Hardy Ale it may be to keep the colour pale.

Will malted oats make any more sense?

“Malted oats are used as a minor blend in the production of stout, whence comes the name 'oatmeal stout'. They certainly provide and add to the nourishing value of stout, and supply useful nutrition for yeast. Such nutrition is much needed when roasted and black malts are in use, as the latter are practically devoid of nutriment. Oat malts have an extremely low diastase, but as the proportion used is very small, this is of no great importance.”
"Brewing Theory and Practice" by E. J. Jeffery, 1956, page 133.

Let’s see if Jeffery is any more accurate in the use of malted oats. Shepherd Neame did, indeed, use it in an Oatmeal Stout. Though, because of the way they parti-gyled, that meant it also ended up in some of the PA, a Bitter. Again, it was about 4% of the grist.

When Maclay brought back their Oat Malt Stout in 1966, obviously the grist included malted oats. Maclay were pioneers of the style in the 1890’s and, just like the early versions, the grist in the 1960’s had a high percentage of oats, around 30%. Which was even more than in 1909, when it was 25%.

Whitbread brewed an Oatmeal Stout until 1950. In contained a tiny amount of malted oats, less than 1% of the grist. This was typical of London brewers who would use just a token amount of oats.

A little earlier than Jeffery, large quantities of malted oats were consumed by British brewers. But that was during WW II when they were forced to by the government after a bumper crop of oats one year. Brewers hated it and dropped it again as soon as they could.

Wednesday, 17 September 2014

Watney Stout quality 1922 - 1925

I just noticed that I'd jumped over Watney. How on earth did I manage overlook them? Not to worry, that will all be put right now.

Since starting this series I've come to have a sneaking respect for Watney's beers. Their consistently high scores can't be a fluke. Yes they were the largest brewery in London and one of the largest in the country. The biggest brewery making the best beer. It's not a situation you'd find today.

I'd thought about publishing a whole load more financial stuff about Watney. But I can't be arsed to traipse through the newspaper archive looking for their annual results for the 1920's. Sorry, but I'm an intensely lazy person at heart. But this one I did find should give a good impression of the state of Watney's finances.

"Watney Combe.
It was announced Friday afternoon that the dividend on Watney Combe Reid stock was to be increased from 17 per cent, to 19 per cent, for the year to June 30 last. The report is now available, and shows trading profits of £1,365,483. This compares with £1,340,735 the year before.

Another £400,000 is placed to general reserve, but it is stated that a similar amount placed to reserve last year has been expended improving properties and converting leaseholds into freehold. The general reserve is £759,455.

The financial position is very sound. There are investments in Government securities for £532,879."
Dundee Courier - Monday 30 July 1928, page 2.

It looks like they were rolling in money. They probably brewed around ten times as much beer as Wenlock Brewery. So you'd expect their profits to be ten times higher. In 1927 and 1928 Wenlock's net profits were £119,201 and £122,047 respectively, meaning Watney's profits were indeed about ten times those of Wenlock.

That's it for the money stuff. I've decided to talk about Watney's other Stouts instead. Like many London brewers, they made several Stouts. They were: Family Stout, Oatmeal Stout, Special Stout and Special Stout for Belgium. All were in bottled form. In addition there was at least one, and possibly two, draught Stouts.

Watney Stouts 1921 - 1929
Year Beer Price size package Acidity OG FG ABV App. Atten-uation
1921 Family Stout 17d quart bottled 1046.3 1012.5 4.39 73.00%
1922 Family Stout 17d quart bottled 1043.9 1010.9 4.28 75.17%
1922 Family Stout 9d pint bottled 1044.3 1012.5 4.12 71.78%
1923 Family Stout bottled 1046.5 1011 4.61 76.34%
1921 Reids Family Stout 9d pint bottled 1045 1010.7 4.46 76.22%
1926 Reids Family Stout 8d pint bottled 1048.5
1927 Reids Family Stout bottled 1047.7 1012.3 4.60 74.21%
1928 Reids Family Stout 8d pint bottled 1050.2 1012.7 4.87 74.70%
1929 Reids Family Stout 8d pint bottled 0.18 1047.8 1007.3 5.28 84.73%
1921 Reids Oatmeal Stout 9d pint bottled 1045.5 1009.7 4.66 78.68%
1922 Oatmeal Stout bottled 1047.4 1009.3 4.96 80.38%
1928 Reids Oatmeal Stout 8d pint bottled 0.07 1050 1015.6 4.46 68.80%
1928 Reids Special Stout pint bottled 1056 1014.7 5.37 73.75%
1921 Special Stout 13d pint bottled 1059 1016.2 5.56 72.54%
1922 Special Stout bottled 1057.8 1015.9 5.44 72.49%
1923 Special Stout bottled 1054.3 1013.8 5.26 74.59%
1922 Special Stout (Belgian sample) 9d pint bottled 1067.1 1023.8 5.60 64.53%
1929 Stout 8d pint bottled 1047 1010.8 4.71 77.02%
1929 Stout 8d pint bottled 0.06 1046 1010.8 4.57 76.52%
1921 Stout 9d pint draught 1053.4 1014.8 5.01 72.28%
1921 Stout 9d pint draught 1054.5 1014.4 5.21 73.58%
1921 Stout 9d pint draught 1045.7 1009.8 4.67 78.56%
1926 Stout 8d pint draught 1053.9
1926 Stout 8d pint draught 1052.7
1926 Stout 8d pint draught 1053.6
1929 Stout 8d pint draught 0.08 1055.9 1014.5 5.38 74.06%
1929 Stout 8d pint draught 0.07 1052.9 1012.1 5.31 77.13%
Sources:
Whitbread Gravity book held at the London Metropolitan Archives, document number LMA/4453/D/02/001
Truman Gravity Book held at the London Metropolitan Archives, document number B/THB/C/252

It's not always made clear in the sources exactly how these beers were branded. Sometimes they are describes as Reid, but others not. Watney seemed to prefer to brand its bottled Stouts as Reid, presumably because, as an old Porter brewery, they would be associated with Stout. Watney's continued to use the Reid name for at least 30 years after the Griffin Brewery in Clerkenwell closed.

Doubtless Watney parti-gyled these Stouts in various combinations. Family Stout, Reids Family Stout, Oatmeal Stout and Reids Oatmeal Stout all look like the same beer to me. I bet they pulled the trick of throwing the odd pound of oats into the grist for all Stouts so they could legally describe some of it as Oatmeal Stout.

Special Stout and Reids Special Stout are probably the same beer as each other and the draught Stout. Though possible they've been slightly tweaked. The Belgian Special Stout probably resembles Watney's pre-war Stout. That's what most breweries did: kept brewing export versions at pre-war strength.

With a couple of exceptions, the rate of attenuation is high, with a couple even over 80%. Were they getting some extra conditioning before bottling?

Right, now on to their draught Stout. It's of the 9d (8d after 1923) type. It's a little stronger and more highly-attenuated than average, but not by a huge amount.  The sample that's only 1046.3 looks like it's a weaker 8d/7s Stout./ Unless it's been seriously watered. But it does look suspiciously like Family Stout. It's been sold at 9d a pint, which screams "cheating landlord" at me.

Will their Stout continue Watney's good run?

Watney Stout quality 1922 - 1925
Year Beer FG OG ABV App. Atten-uation Flavour score Price
1922 Stout 1014.7 1057.7 5.59 74.52% clean 1 9
1922 Stout 1012.4 1055.9 5.67 77.82% good 2 9
1922 Stout 1013.2 1056.2 5.60 76.51% good 2 9
1922 Stout 1012.8 1054.8 5.47 76.64% poor -1 9
1922 Stout 1013.7 1055.2 5.40 75.18% yeast bitter -1 9
1923 Stout 1013 1056.5 5.66 76.99% fair 1 9
1923 Stout 1013.6 1056.1 5.53 75.76% fair 1 9
1923 Stout 1015.2 1056.2 5.33 72.95% good 2 8
1923 Stout 1010.8 1046.3 4.61 76.67% only fair 1 9
1923 Stout 1012 1055 5.60 78.18% v fair 2 9
1923 Stout 1013.2 1055.2 5.46 76.09% v fair 2 8
1923 Stout 1013.8 1054.8 5.33 74.82% v fair 2 8
1923 Stout 1012.5 1054.5 5.47 77.06% very fair 2 9
1924 Stout 1015.4 1053.4 4.93 71.16% good 2 8
1924 Stout 1013.2 1054.9 5.43 75.96% v poor -2 8
1925 Stout 1015.4 1055.9 5.26 72.45% good 2 8
Average  1013.4 1054.9 5.40 75.55% 1.13
Source:
Whitbread Gravity book held at the London Metropolitan Archives, document number LMA/4453/D/02/001

Yes, it will. Thirteen from sixteen achieved positive scores, including 9 2's. The overall average is a very decent 1.13.

It'll feel weird seeking out Watney's pubs when I'm holidaying in the 1920's. But they're probably the safest bet.