Lower the oven temp to 300F
In a food processor add the graham crackers and brown sugar, process until only crumbs are left. While the food processor is still running, add the melted butter and process until it resembles wet sand.
Line a 9X13 pan with parchment paper making sure the parchment comes up and over the sides of the pan. Press crust into the bottom until well compacted.
In the bowl of a stand mixer, add the brown sugar, white sugar and cream cheese. Mix until well combined. One at a time, add the eggs and vanilla, mixing until well combined, scraping the bottom, before adding more.
Add the pumpkin puree, cinnamon nutmeg and salt, mix until very well combined.
Add the beer and stir until combined.
Sprinkle the flour over the bowl, stir on medium speed until just combined.
Pour over the crust.
Bake at 300F for about one hour or until the center no longer sloshes when gently shaken but just slightly jiggles (The secret to a great cheesecake is not to over bake it, it's better to slightly under bake it for a smooth mousse like texture).
Chill until set, about 3 hours.
Remove from pan using the parchment paper. Cut into squares, top with pecans.