I think this is a GQ.
So, I went to the liquor store to see if they had the little bent up spoon like device that bartenders use to poor a black and tan when it comes time to add the Guinness. They didn’t have any, but the guy told me they’re called spoons, and he implied that any old spoon will do.
Well, not in my case. At least, not so far. So, is it doable with a regular spoon? If so, what’s the trick?
:sips dark tan:
Bend spoon to ~ 65degrees. Hold upside down. Go slow. It helps to practice.
Dude…they’re spoons.
Take one (1) spoon. Bend it at a right angle, so the bowl faces the end of the handle. Pour one-half pint ale. Holding the bowl of the spoon 3.67 mm above the ale, gently pour stout into bowl of spoon. Raise the level of the spoon to maintain the required 3.67 mm separation. When full, place spoon in sink. Imbibe. Smile. 
pour very very very slowly over a big spoon.
We have a black and tan spoon with ‘guinness’ printed on it, but we never use it.
Colour me ignorant, but where does the bend in the spoon come in if you’re pouring into the bowl of the spoon anyway? I am going to venture a guess - otherwise, you can’t lower the bowl of the spoon to the required 3.67mm. The forehead-slapping smiley from you will confirm my guess as accurate.
You pour over the back of the spoon, not into the bowl. The idea is to slow down and disperse the stream of Guinness so that it doesn’t mix with the Bass. IIRC, the only purpose of the u-shaped bend in the spoon is to hold it on the rim of the glass, freeing your hand to handle another tap (tres important at the 10 min-to-call rush).
I’ve poured B&T’s in bars (well, a couple) and at home, and I’ve never been able to make them come out perfect out of the can. No matter how gently I pour, there’s always a significant amount of boundary mixing. I got worried about this at one point (losing my touch?) and under the guise of showing the new girl at my favorite haunt how to pour a proper B&T, I tried it out; again, no problem from the tap.
I don’t know if it’s the Guinness or the Bass at home (I can immediately taste the difference of both from the bottle vs. tap), but I have noticed that when the keg of Guinness is almost killed, it tends to mix more readily. Presumably there is some addional aeration in the line causing this.
Ditto with Half & Halfs. YMMV.
Stranger
I’m guessing at this point that the spoon helps with dispersal, but that much of it is in the pour, or, if you will, the touch. A bartender able to set a Guinness tap on a very slow, and steady, pour over a spoon designed to clasp on to the glass has something there that the homeboy doesn’t.
Ah, well, how d’ya get to Carnegie Hall?
Depending on who you talk to, a proper pour of Guinness takes between two and eight minutes. Enthusiasts/connoisseurs will affect a haughty attitude if presented with a rapidly poured, flat-headed glass of alleged Guinness.
Even with that in mind, though, I can’t get 'em to work out right at home. I can get close, but not that perfect, razor sharp boundary you get off the tap.
Stranger
Is this a whoosh? Am I missing something here? 3 and 2/3 of a millimeter? That sounds like exactly the sort of measurement no one would ever get right in a bar. In dim light. By sight.
I don’t know if it’s still the case, but one of Chicago magazine’s criteria for rating bars in their annual survey was the amount of time the bartender took to pour a Guinness (longer was better). As I recall, the winner a few years ago took over 10 minutes to pour one. They recommended ordering two at the outset, so you could drink one while the other was pouring, and then stay one ahead for the rest of the evening.
When pouring one at home, I always have the bowl of the spoon facing up. That seems to disperse the stout across the top of the ale, with little boundary mixing. It’s not as pretty as the ones I get at my local, but it works.
Buns3000, consider yourself :smack: .
Crandolph, yes it was a whoosh. The idea is to keep the spoon very near the top of the liquid, to minimize splashing.
I tend to have better luck with a half & half than a Black & Tan for some reason. I don’t know why.
Hey it’s “worth waiting for” but, damnit, I want my beer!
And you can’t really drink anything else before Guinness, lest the hoppy nature of any decent lager render your taste buds complelely unable to appreciate the nuances of Guinness.
I don’t mind waiting a bit, but I need something in my hand, and I can only spend so much time rolling a quarter or tying knots in stirsticks one-handed. 
Stranger
Don’t forget that it needs to be the “draught” Guiness in the can with the little carbonation canister in the bottom not plain Guiness in the bottle and don’t let it sit after opening the can but pour immediately, slowly, over the back side of a large spoon.
Taught to me by my brother in law who works for Guiness Imports.
It’s never going to taste as good as a B & T from the keg though.
Thanks. I figured that was probably the case; also thought that someone may have actually taken the time to measure the ideal!
By the by, if you belly up to the bar and simply order a “Black & Tan” in these parts, you’ll get a bottle of the Yuengling product of that name, which is their pre-mixed lager and stout brands. Heresy for many, I know. Otherwise you’ll have to specify that you want the traditional tap-based concoction (in all but a few realtively more genuine Irish bars).
Success! Using the Guinness with the CO[sub]2[/sub] cartridge seems to make a difference, but I also slowly draw the spoon up the side of the glass while pouring. Thanks, all.