Beer style origins

About 1720 is the best guess. But it didn't come out of thin air. That's when London brewers started ageing their Brown Beer themselves. This is what came to be known as Porter. But Brown Beer had been around for quite a while before that. And third parties had aged it before 1720. It's all very complicated.

As an identifiable, specific style, I'd go with about 1720.

 

Do you see a trend toward "style-ization" following from porter or just it being the first instance and other styles crystallizing at other points for their own reasons?

 

Yes. Associating a type of beer with very specific characteristics seems to begin with Porter.

Mild Ale doesn't really become what we would call a style until the early 19th century. Before then it's just a blanket term for any Ale served young. By 1830, at least in London, it's become a beer with specific characteristics.

It's the same with Stout. It starts off as just meaning any strong beer, then becomes the term for specifically a strong form of Porter.

Don't get me started on Pale Ale or Brown Ale.

 

Haha but why not? You wouldn't go on at length would you?

My question was more about whether the appearance of porter as a more defined style inspired brewers to work toward defining other styles or if the appearance of more formalized definitions of mild and stout (for instance) arose for their own reasons

 

It's all to do with industrialisation and standardisation. Porter was the start of that process and other styles followed.

 

The Carlsberg Foundation has published transcribed letters from JC Jacobsen and Carl Jacobsen which contain alot of interesting information about lager beer brewing in the 1860s-1870s (all in Danish however).

In a letter from 16th of May 1868 Carl Jacobsen writes:

In a letter from 18th of May 1868 Carl writes:

JC and Carl Jacobsen use the term gammelöl (old beer) to refer to summer beer/lager beer, and ungt öl (young beer) to refer to winter beer/schenkbier/abzugbier. So as per the first letter Carl arrived two days before the lager beer was being tapped, mid May. The first of May had traditionally been the start of summer beer season in Bavaria, the first month when the summer/märzen/lager beer brewed in the winter was allowed to be served and by which time the serving of winter beer could no longer take place (regulations which would be abolished in Bavaria in that same time period).