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.