Warm Beer

Almost never.

Although somewhat subjective, ales tend to taste best when served at or slightly below "cellar temperature" while lagers taste best somewhat below that, on the warm end of "refrigerator temperature." So if forced to give ranges I'd put ales somewhere around 8-14C (46-57F) and lagers around 5-8C (41-46F). Here's an interesting essay on the topic:

Only if you're a barefoot girl sitting on the hood of a Dodge...

"eddie wilson" eats posts like this for lunch news: snipped-for-privacy@i40g2000cwc.googlegroups.com:

Soft summer rain is optional?

the 40's, a good ol' cold beer in that range!

Depends what you mean by "warm".

I find that the lighter an ale (all lagers should be cold) the colder it needs to be right down to just-a-bit-warmer-than-the-fridge. (Its like wine - the paler the colder. I mean you're not going to chill a bottle of Chateau Petrus, are you?).

Standard ales are best served at "cellar" temperature or above. They've been designed to be served straight from the cellar. In particular light-bodied ales need that slight "cellar" chill, just like a light bodied Beaujolais. Chunkier, darker and fuller bodied beers should be served at ambient temperature. (Its like wine - dark, chunky wines need some temperature. I mean you're not going to chill a bottle of Chateau Petrus, are you?).

This is why I said it depends on what you mean by "warm" - for most people ambient temperature is practically "hot". It's not - for a trappist double (triple is light in colour see above) it needs to be ambient to taste it, the same with a chunky ale such a Shepherd and Neame's Spitfire. Actually Spitfire is supposed to be served non-fizzy which makes it easy to stiplulate - with a bottle of Spitfire as apposed to the "real thing" I pour it cellar temperature and then wait for the fizziness to go - THAT's the right temperature.

I've only had a decent darkish ale too hot when I have left it in the sun in a barbecue. Actually WARMED as opposed to NOT COLD is not very palatable.

I would use the rules others have given as a guideline and experiment. My brother's home brew ginger porter is perfect at about 50 degrees.