Rauchbier smoke source

I can't speak to smoked malt vs. liquid smoke.

But to answer your other question, there are big flavor differences between the types of wood you use, at least in cooking, so I would think it depends on the characteristics you want to impart in your beer. Here's a list I reference for the flavor profiles of different smokes (with a few I've added myself):

• Oak : A heavy smoke flavor.
• Hickory: Strong, smoky taste.
• Mesquite: Sweet, light taste.
• Pecan: Nice taste. Lighter than hickory.
• Apple: Sweet, fruity smoke taste.
• Beech: Milder and sweeter than Hickory with a slightly fruity flavor.
• Acadia: Similar to mesquite, but not as strong.
• Almond: A nutty, sweet flavor.
• Alder: Very delicate. Slightly sweet.
• Apricot: Milder and sweeter than Hickory.
• Ash: Burns fast. Light, but distinct flavor.
• Birch: Slightly sweet.
• Cherry: Slightly sweet fruit flavor.
• Grape Vines: Similar to fruit woods.
• Grapefruit: Medium smoke flavor. Slight hint of fruit.
• Lemon: Medium smoke flavor. Slight hint of fruit.
• Lilac: Very light smoke flavor.

According to BeerAdvocate, Rauchbier uses Beechwood to smoke the malt.

I've never used liquid smoke before. Having said that, I think this calls for an experiment! For your first question (detecting difference in complexity between liquid smoke vs. smoked malt), try it! Make both, try them, and let me know :)

As an aside, when does one normally add liquid smoke?

As for your second question, about "better", that's a question of preference.

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