Rauchbier (smoked beer) is one of the less-common styles in the market (though I think it's due for a resurgence once we all get tired of this onslaught of barrel-aged beers), and while it's wonderful it's also the source of a lot of undeserved mystery and confusion. Let's clear some of that up - this is a simple beer, and my recipe (below) will have your LHBS grain attendant thanking you for taking it easy on him/her this Christmas week.
A Brief History of Smoked Beers
Very brief, in fact. Once upon a time, almost all beers were smoky. Maltsters dried and roasted malts over wood fires, and they produced smoke, which imparted a smoky flavor to the malt itself. As smoke-free sources (coal fed ovens, primarily) became commonplace, malts became "clean" except for those that wanted to be smoky, and smoked beers became a retronym-labeled thing.
Wow, That Was Brief - now what?
None of that helps us, really, since the question now becomes, "If I want to make a Rauchbier, how much smoked malt do I use?" Ironically, few things scare me as much as homebrewers who say "I read it on the internet" as justification for their brewing practices. But I want you to take this piece of internet trivia to heart:
IT DOESN'T MATTER HOW MUCH SMOKED MALT YOU USE.
How do you Know?
Well, I know because I brew Rauchbier two to three times per year, and because I get a lot of objective feedback on it! Over the years I've adjusted my Classic Rauchbier recipe a number of times, looking for this magical percentage that will produce the best one, and in doing so I've completed a good natural experiment.
When I started, I didn't want to overpower what is, essentially, an Oktoberfest plus smoke with an excess of smoked malt flavor/aroma, so my first attempts were pretty conservative and in line with the internet wisdom of that bygone age of 2008. I stuck to about 25-30% of the grist, making up the balance with straight Pils, Munich, and Maris Otter (I use Maris Otter for damn near everything - more on that another time). It made for a pleasantly smoky lager. Good stuff.
But I wanted to go smokier - after all, anyone who's making a smoked beer has the Schlenkerla angel (devil?) lurking on one shoulder, muttering in a German accent in their ear, "You know, vee haff a much smokier beer zahn you..." So I upped the percentage of smoked malt. And upped it again. And again.
And you know what? No real difference in the smoke level. It increased a bit, but certainly not to any level where I said, "whoa, back it off."
Until I hit my limit. 97%. That's what I currently use in my Rauchbier. And I've actually had competition judges tell me to "increase amount of smoked malt" - right, except that wouldn't address the problem! [Take note, BJCP Exam preppers...]
Not How Much, But What Kind
It isn't how much you use, but what the maltster did to your malt in the first place that makes the difference. In that way, it's kind of like when you use malt extract: you're at the mercy of whomever created it. So what do different types do?
First, let's just acknowledge that peat malt is disgusting. But beyond that, it's a crazy intense smoky/phenolic flavor producer, so use it sparingly (or not at all).
The classic version is beechwood smoked malt, and at least one commercial brewery I'm personally acquainted with actually uses the same maxed-out levels of beechwood smoked malt that I do.
But you can use other wood types as well. Apple and cherry wood are quite common and can be used at very high levels. I read that you can do the same with mesquite or hickory, though I admit I have no experience with them.
So the moral of the story is: Don't be afraid of smoked malt. Using it sparingly might produce somewhat subtler smoke flavors (only "might," though - one of my early attempts came out crazy smoky despite being only 40%), but using more almost certainly won't make your beer too smoky. It will, though, almost guarantee that people can tell it's a smoked beer, which I'm assuming was the point of your brewing of it in the first place.
Recipe, Discussion, and Uses
The recipe below is a favorite of mine, and it's just about as simple as simple beer gets.
OG: I shoot for about 1.050, but you can raise/lower to your ABV goal/liking!
Briess cherry wood smoked malt: 97%
Melanoidin malt: 2%
Black Patent malt: 1%
25 IBUs of your favorite bittering hop added at 60 minutes
About an ounce per 5 gallons of your favorite German noble hop (Hersbrucker is my preference) added at flame out
Wyeast Munich Lager yeast (#2308), but German Ale (#1007) can be fun, too
Ferment cool (52F for the lager yeast, 62F for the ale yeast) and enjoy!
The small malt additions there, I've found, make a pretty big impact. The melanoidin addition adds a touch of rich bread in the background, and the black patent adds a note of dryness without adding any real "roast" flavor - I find that smoky beers tend to come across as a bit sweet.
The hopping is there just for a touch of complexity and enough bittering to balance the sweetness, but this is definitely a malt-centric beer.
And as for yeast, use whatever you like for Oktoberfest, but as I noted above you can get some fun fruity/berry esters out of the German Ale yeast as well, and they seem to complement the beer nicely.
Rauchbier makes for an outstanding cooking beer as well as an easy-drinking pint, and it makes for a great base for marinades! I've also injected it directly into roasting meats, with very good results.
And as for smoking your own malt: I'm not that guy. Sorry.
The simple takeaway here is that smoke malts are like most other things these days: user-friendly. It's pretty difficult to hurt your beer with these (except the aforementioned monstrosity that is peat malt), so swing for the fences!
Keep it Simple.