black and tans

[monkeybrewer]

I was wondering if anyone out there in forum land has a good rule of thumb for the difference in final gravities of two beers to be able to float one on another. Thanks in advance for any help.
Cheers
Jay Brown
Brewmaster
Legends Sportsbar and Brewpub
Plattsburgh, NY

[hophead82]

black and tan's are tasty

I thought that what made a black and tan was the nitrogen/carbon dioxide mix that guinness is expelled with. Its my understanding that the nitrogen makes the smaller bubbles, less surface tension, and a lighter overall density that makes it "sit" on any beer. Hope this helps!

[BeersmithMT]

I have never heard or thought about the difference in gas composition. I have always believed it's the difference in SG that allows the beers to layer. Black & Tans were around decades before Guiness started putting nitrogen into beer. I have assumed it's the very low final gravity of Guiness Pub Draught that allows it to float on top. That being said, I have successfully made upside down Black & Tan's with a Pale Ale @ 1.012 and a Stout at 1.020.

[monkeybrewer]

upside down black and tan...great idea!

I'm sure that I'm with beersmith about it being all about a difference in SG and a gentle pour. I'm hoping I can get a 7 point difference in SG to float. I'll let you know who it goes. It would be nice to know if there was some density equation out there that spelled it out exactly. Oh well...I guess beer can't always be an exact science. Thanks for the responses guys
Cheers

[plaztikjezuz]

i have gotten beer to float with a temperature difference of about 3-5 degrees.
i also use a bent spoon to break up the pour. no drilling into the light beer.

but i have never heard about the SG and heavy and light beer until about a week ago, i was told years ago that there was a temperature difference in the two, and the warmer beer went on top. which for me makes since with physics but then so does the density of the liquids.

what i used to do since my taps are the same temperature is i would pour the stout into a pitcher and let it warm a little then float it on the tan.

[monkeybrewer]

great info

Thanks for keying me into the other way to affect the density of the two beers...temperature! I'm going to use that technique along with a good difference in SG. I'm sure I'll be able to float my stout now. Thanks for the great ideas.
Cheers

[PatFiori]

density

Hey guys,

My guess is that there is not one specific way to create layering. It's all about having two different densities, anyway you want to go about doing that should work. The only problem I have is with the temperature. As the beer sits with the customer and starts to warm up, shouldn't it start to mix and blend more than a gravity or gas induced black an tan would?

Patrick Fiori

Brewery Manager
Clocktower Brewpub
Ottawa, Ontario

[monkeybrewer]

temp worry

I guess my hope would be that as long as the two beers started out at different temps they would keep a differential even as the ambient air warmed both (at least for the short time it takes to consume a pint). That and hopefully by that time, the customer has already sipped it a few times to skew the layers a bit anyway. Thanks for the response.
Cheers

[NYSBrewer]

If you are pouring off a system where the lines are cooled with a glycol system, the beers should be the same temp. We constantly run a black and tan on our menu and it is a mixture of our house amber ale and our house stout. The stout is on nitrogen. I have found the final gravities matter more than the starting gravities. Your stout should finish lower than the beer you are trying to float it on. ie: FG: 1.014, amber to a FG: 1.010 stout.

[mr.jay]

black and tans

quote - "black and tans were around long before guiness dispensed with nitrogen."

i'm not a historian, or from the emerald isle, so don't take what i say as gospel, but most pubs i visited in ireland just let them blend together in the glass. one bar keep told me that layering the 2 was something us "yanks" invented. while they didn't have the eye appeal i was used to , they certainly tasted great, especially off the engine!

[plaztikjezuz]

quote - "black and tans were around long before guiness dispensed with nitrogen."

i'm not a historian, or from the emerald isle, so don't take what i say as gospel, but most pubs i visited in ireland just let them blend together in the glass. one bar keep told me that layering the 2 was something us "yanks" invented. while they didn't have the eye appeal i was used to , they certainly tasted great, especially off the engine!

i have never been to the UK but i also have read this, i would also like to point out, that in ireland the term "black and tan" is politically charged if i remember right they call them a dark and mild or a half and half. but hey they also call squares "fags" so who the hell knows or is that england?

here is a nice source of some history and practice. they list both methods in the thread as a combined method to produce the drink.

http://www.ivo.se/guinness/bnt.html

ok i have to post this here because i just amended wikipedia to include in the variations list our variation which we called "Dumb and Dumber" when michigan brewing co made a barley wine i would get cornies of that and the RIS and we would make black and tan's out of those two. it did catch on at the pub when the two were on tab together, limit 2, lol.

http://en.wikipedia.org/wiki/Black_and_Tan

[jason.koehler]

Maybe a rookie physics question here, but what has more density, a cold beer or a warmer beer?

I would think that molecules expand when warmer, and shrink when colder, so a cold beer like a lager would be more dense than a warmer beer like an ale...which should be condusive for a decent half and half you'd think...lager on the bottom, ale on the top...the more dense beer on the bottom, yadda, yadda...am I making sense?

Ahhh, why did I take geology as my lab science requirement instead of physics??

Plate tectonics anyone?

[monkeybrewer]

warm vs cold

colder liquids are more dense than warmer ones (as long as we are talking about the same liquid). I think the best illustration of this in the brewery is your hydrometer, which needs temperature corrections. The colder the liquid, the higher out of the liquid is the hydrometer and therefore more dense than the same liquid at a higher temp. Hope that makes sense.
Cheers