German brewing in 1966 – bottling

This really is, finally, the end. Though I’ve just noticed that I’ve not one but two later JIB articles about German brewing. It’s going to be a long, dark winter.

You may remember that I ran a long series about bottling in Britain. I’m weirdly fascinated by the process of making non-bottle-conditioned beers. It’s an area where there was a great deal of progress in the first half of the 20th century, mostly following the lead of the US brewing industry.

But I digress. We’re supposed to be discussing German bottling.

We begin with something about the oxygen content of bottled beer:

“Developments in Bottling
As a result of pasteurization and the increase in storage times, particular interest is being shown in the oxygen contents of bottled beer. Filter-sterilized beers are also oxygen sensitive, but not to the same degree as flash-pasteurized or bottled pasteurized beers.

Filtered beer brings a certain air (i.e., oxygen) content with it to the filling machine; this can vary, according to treatment, between 0.15 and 0.5 mg. per litre. The oxygen content can be increased in the filters and also by collecting in air-filled bright-beer tanks, and subsequent resting at a high air-pressure level. In these cases, pre-filling of the tanks with CO2, the use of deflecting plates and the washing of the beer with CO2 can improve matters. During the actual filling of the bottle the greatest danger of oxygen absorption occurs.”
Journal of the Institute of Brewing, Volume 72, Issue 1, January-February 1966, page 23.

By longer storage times it doesn’t mean lagering at the brewery, but the greater length of time packaged beer spent in the distribution change with the move from pub to home consumption. The more oxygen in the beer, the quicker the bottle would spoil.

“The ring-canal bottling machines give better results than the tank type. The air uptake of the beer is increased during filling of the bottle if high air pressure has to be applied, owing to the use of bottlers without tubes, or to beer with a high CO2 content being bottled with cock fillers. For the same reason, shortened filling tubes, intended for the filling of various sizes of bottles, are not desirable.”
Journal of the Institute of Brewing, Volume 72, Issue 1, January-February 1966, page 23.

What’s a ring-canal bottling machine? I would tell you, had I any idea. But a search on the internet came up with zilch. Please tell me if you know what the hell it is and how it differs from a tank type bottling machine.

Isn’t filling the bottle with CO2 the way to keep oxygen out? Apparently not.

“Prefilling of the bottle with CO2 has little success unless the bottle has previously been evacuated or the old Seitz method of CO2 rinsing is used. With this system, the air-CO2 mixture in the bottler is used to prefill the bottle entering the bottling machine.

Pre-evacuation and subsequent prefilling with CO2 is used for hot bottling, and it was this method which helped the hot-bottling system to become acceptable. By causing the beer to foam out of the bottle useful air values can be reached. This is achieved by regulation of the bottling pressure, temperature, CO2 content (more than 5 g. per litre) or by tapping or use of ultrasonic devices. However, it has to be guaranteed that all taps on the bottler work in a similar manner and this is a problem that cannot be solved without special assistance.”
Journal of the Institute of Brewing, Volume 72, Issue 1, January-February 1966, pages 23 - 24.

Bottling on foam is what that’s called. Which seems to be the desirable way to go. I discussed this with a brewer in the US recently. Where was it? Their old bottling machine only achieved the right level of foam on some of the filling heads. It meant that some bottles had a very short shelf-life and couldn’t be shipped very far. A new machine with capped every bottle on foam greatly increased shelf-life and had opened up new distribution possibilities.

How much air was acceptable in a bottle?

“My own results (which have recently been confirmed by Kipphahn) showed that a detrimental effect on the flavour of the beer occurs when the air value is in excess of 1.5-1.8 ml. per half-litre bottle.”
Journal of the Institute of Brewing, Volume 72, Issue 1, January-February 1966, page 24.

Briggs recommends even less than that:

“A successful bottling line should allow the brewer to:
 maintain the dissolved oxygen level in the beer to at least less than 0.2 mg/l, although there are now reports of plant able to meet a specification of less than 0.05 mg/l”
"Brewing: science and practice", by Dennis E. Briggs, Chris A. Boulton, Peter A. Brookes and Roger Stevens, 2004, page 761.

What did the future hold?

“The introduction of CO2 bottling has produced considerable improvements in beer flavour, particularly with regard to flash pasteurized beers, hot-bottled beers and bottled pasteurized beers. Of the various possibilities, hot bottling would seem to have the greatest promise for future development.”
Journal of the Institute of Brewing, Volume 72, Issue 1, January-February 1966, page 24.

Was hot-bottling the future? It doesn’t seem so. I can’t find any mention of it in Briggs. He describes a different method of getting the beer to foam before capping:

“It is essential en route to the crowner to eliminate air from the head space of the bottle to avoid subsequent oxidation of the beer. This is now usually done by water-jetting. A high-pressure stream of sterilized water is sprayed onto each open bottle. Only a few ml of water enter the bottle but this causes an effective beer foaming, which rises in the neck and dispels oxygen and prevents any further entry. This process is carefully adjusted to minimize beer loss. Liquid nitrogen jetting may also be used (Donovan et al., 1999). This technique reduces beer losses and, perhaps more importantly, reduces waste. The foam is formed initially around the nitrogen gas and it is not necessary to expel foam containing air and losses are lowered.”
"Brewing: science and practice", by Dennis E. Briggs, Chris A. Boulton, Peter A. Brookes and Roger Stevens, 2004, page 779.

That really does sound weird, spraying water into a newly filled bottle. But I suppose it must work.

And that’s us done with Narziss. And German post-war brewing. For the time being. There are those other two articles.