Heineken (Rotterdam) output in 1939

Having access to every single page of Heineken's wartime brewing records means I can do all sorts of fun stuff. Like trawling through them recording every gyle: beer, batch size and OG.

This give me access to all sorts of interesting and useful data. Like exactly how much of each beer they brewed in a year. Getting hold of that information was my main motivation. But I also get to see how much beer they brewed month-by-month and its average OG.

I'm dead glad that I did. It's revealed some unexpected insights. The first being how much the quantity they brewed varied from month to month. In November they brewed over 35,000 hl, but in August fewer than 11,000 hl. That's a huge difference. Far larger variation than I've ever seen at a UK brewery. And a very different pattern

At Whitbread, the summer was the peak brewing season, with the greatest amount brewed in July, followed by August. It was the exact opposite at Heineken, with those two months being the slackest. I know why Whitbread brewed more in the summer - people drank more beer during warmer weather. But why would Heineken brew less then? Could it be because, if they were lagering for any length of time, beer had to be brewed months in advance?

Second surprise was the average OG. 11.2º Plato is 1044.86 in SG.Not a huge amount greater than the UK average of 1041.02 (1937). I would have expected a continental brewery's average to be quite a bit higher than the UK's.

Heineken (Rotterdam) output and average OG by month
month	year	hl	grav. Points	average OG
Jan	1939	33,594	383,843.9	11.4
Feb	1939	30,712	350,098.1	11.4
Mar	1939	21,793	237,043.0	10.9
Apr	1939	21,178	232,720.9	11.0
May	1939	21,015	230,321.8	11.0
Jun	1939	29,354	329,148.0	11.2
Jul	1939	12,968	138,059.7	10.6
Aug	1939	10,887	129,107.3	11.9
Sep	1939	26,980	301,120.3	11.2
Oct	1939	34,986	395,410.6	11.3
Nov	1939	35,207	393,956.5	11.2
Dec	1939	20,379	232,225.5	11.4
Total		299,053	3,353,056	11.2
Source:
Heineken brewing records held at the Amsterdamse Stadsarchief, documents number 834 - 1758 and 834 - 1759.

Whitbread Ale output by month
month	year	barrels
Jan	1939	29,574
Feb	1939	30,114
Mar	1939	35,865
Apr	1939	39,817
May	1939	36,053
Jun	1939	42,091
Jul	1939	44,130
Aug	1939	40,878
Sep	1939	37,476
Oct	1939	33,246
Nov	1939	35,365
Dec	1939	39,100
Total	1939	443,709
Source:
Whitbread brewing record held at the London Metropolitan Archives, document number LMA/4453/D/01/103.

Heineken (Rotterdam) output by beer in 1939
Beer	OG	hl	%
Bok	17.2	1,713	0.57%
Mei	15.2	2,163	0.72%
Bei	12.5	4,435	1.48%
Do	8.9	26,429	8.84%
Li	8.9	41,036	13.72%
P Exp	11.8	43,004	14.38%
P	11.8	180,273	60.28%
total		299,053
Sources:
Heineken brewing records held at the Amsterdamse Stadsarchief, documents number 834 - 1758 and 834 - 1759.