To add a bit of detail to the existing answers, the primary method for adding a smoked flavor to beer is by using malts that have been dried over a smoky fire, rather than in a kiln which allows the malt to absorb compounds from the smoke that they then release into the beer during brewing. Some of the oldest smoked beers still produced are German (...
Well, Saison is quite a broad category simply because it comes from a broad definition.
The original term comes from regular strength light ales ca. 3.5% abv) brewed during the Autumn in Belgium, and stored for drinking in the summer by farm workers. (Hence the pseudonym "farmhouse ale".)
As wikipedia states:
Historically, saisons did not share ...
Start with a normal malt
put malt in a large metal screen
COLD smoke for a few hours (if you add heat it will also add color to the malt)
Let sit for a day or so.
brew beer with it
enjoy something not many get to taste, yet alone the possibilities of different woods to use for the smoking make it an unused "5th" beer ingredient.
How to Smoke ...
I agree with mdma that it's traditionally more of a historical definition than a stylistic one. To expand on their answer, though, in 2008, the BJCP defined a saison as the following (abridged):
Aroma: Moderate sweetness with light, grainy, spicy wheat aromatics, often with a bit of tartness. Some coriander, with a complex herbal, spicy, or peppery note in ...
One source of smokiness unmentioned as of yet is vinvyl-guaiacol production from bacteria metabolism.
The answers already given are more relevant, however there is one important source that has been unmentioned. Although more common in distilling, lactobacillus and other strains of bacteria can attribute flavor to fermentation products. Different strains ...
One other potential source of smoke flavors is actually the yeast. Some yeast produce phenolic compounds during fermentation that produce smoke flavors and aromas. Scottish yeast strains in particular are known for this.
I don't think that there is a commonly accepted glassware for saisons in general. Different sources point to 3 different types: the pint, the tupic, and the oversized wine (goblet?). A prticular saison may be better suited to one of those three, depending on whether it was crafted to have more or less aromatic, or just a beer for simple drinking.
There was another source that I read (probably that 1000 page beer encyclopedia that I forgot the title of) where they said that a saison was made with whatever ingredients that were available at hand at that season.