Summit Brewing's latest addition to its ambitious Unchained Series is finally here. The Imperial Pumpkin Porter, the fifth beer in the limited-time-only series, is getting several release parties this week. Each entry into the Unchained Series features a different Summit brewer basically doing whatever he wants. This time its Nate Siats, who wanted to create a beer that would go with the season.

The Imperial Pumpkin Porter is his version of a dark, strong porter with pumpkin spices. In the above video, Siats describes the creation of the beer and even takes viewers to the local farm where he picked the pumpkins. The organic farm is owned by another Summit employee, Charles Jones (who works on the keg line). The beer is available on draught this week and in bottles around mid-November.

Check out the release-parties below:

5 p.m. Wednesday, Oct. 27: Stub & Herbs.

7-9 p.m. Thursday, October 28: Stella's Fish Cafe.

4-6 p.m. Friday, October 29: The Happy Gnome.

More info on Summit here. Check out Summit's blog here.