In Charles Dickens’ 1850 piece “Three Detective Anecdotes”, the policeman Inspector Wield reports this attempt to get information from a witness:
When the play was over, we came out together, and I said, “We’ve been very companionable and agreeable, and perhaps you wouldn’t object to a drain?” “Well, you’re very good,” says he; “I SHOULDN’T object to a drain.” Accordingly, we went to a public-house, near the Theatre, sat ourselves down in a quiet room up-stairs on the first floor, and called for a pint of half-and-half, apiece, and a pipe.
What’s half-and-half? I asked myself.
Modern references (Beer Advocate, amongst others) say that half-and-half is a cousin or a variant of “black-and-tan”, and that it’s made by mixing pale ale and and stout. In fact, they specify a mix of Guinness and a “mild or bitter beer”. Dickens’ characters probably weren’t drinking Guinness, though.
An even earlier source – an 1820 treatise against the adulteration of food (Project Gutenberg e-text) – covers half-and-half in more detail. The author says that “every publican has two sorts of beer sent to him from the brewer… ‘mild’, which is beer sent out fresh as it is brewed; the other is called ‘old'”.
Half-and-half is a mixture of the two. So, instead of paying for a full pint of the “good stuff”, the consumer could shave a little off the cost by voluntary adulterating their beer. Presumably, they might also choose to do so because the aged beer was sour, and so a bit much to take on its own.
And it was in trying to come up with a quicker and easier way to serve mixed beer that London landlords invented “entire butt” (beer pre-mixed in the barrel, and coming from one tap) which in turn became the famous London Porter. Roger Protz and Graham Wheeler, in their excellent if eccentrically typeset Brew Your Own British Real Ale at Home argue that “the original London Porters were simply brown ales that were deliberately soured”.
So, how to simulate a pint of Victorian half-and-half? I’d guess that getting two similar beers (brown ales), souring one, and keeping the other fresh, is the best way to start. Failing that, a dash of something lambic in a brown ale might do the job.
I came across “Three Detective Anecdotes” in A Treasury of Victorian Detective Stories edited by Everett F Bleiler (Harvest Press, 1980), but it’s also available at Project Gutenberg for free.