[mauvehaus]

My understanding is that MGP makes rye whiskey for just about everyone because of the complexity of dealing with rye grain (not a distiller; can't offer more detail). Many distilleries make their own bourbon or other American-styles whiskies including Tennessee-style, etc.

Some brands of non-rye whiskey are, of course, contract-distilled just like most of the rye whiskey. I don't know whether Bulleit Bourbon is contract-distilled or made in-house. I do know it makes a pretty fine Manhattan. I would be surprised if Bulleit Rye is made in house.

[teh_klev]

You can still probably produce a unique and good "craft" product even using spirit from large scale spirit producers such as MGP.

In Scotland it's not uncommon to see "independent" bottlers. These are specialist companies that will take spirit from mainstream distilleries and then mature the whisky in their own casks. After maturation these independent bottlers will bottle under their own branding and possibly choose more traditional post processing. e.g. choosing not to add caramel colouring (E150A) or choosing not to use chilled filtration. You often end up with a much different product than that of the distillery you sourced your raw spirit from.

Maybe this is what Bulleit are doing?