Spiced ale tastes like burnt plastic

My first AG was a spiced ale for fall. I was hoping it would all mellow and taste good, but the weird aftertaste will no go away. It tastes like an ale Marzen, but that aftertaste is just wrong. Here is my recipe:

Type: All Grain
Date: 8/31/2007
Batch Size: 5.00 gal
Brewer: Jake
Boil Size: 6.41 gal Asst Brewer:
Boil Time: 60 min Equipment: Brew Pot (7.5 gal) and Igloo Cooler (10 Gal)
Taste Rating(out of 50): 35.0 Brewhouse Efficiency: 70.00
Taste Notes:

Ingredients

Amount Item Type % or IBU
6.00 lb Pale Malt (2 Row) US (2.0 SRM) Grain 61.54 %
1.50 lb Munich Malt (9.0 SRM) Grain 15.38 %
1.00 lb Honey Malt (25.0 SRM) Grain 10.26 %
0.50 lb Caramel/Crystal Malt - 80L (80.0 SRM) Grain 5.13 %
0.50 lb Special Roast (50.0 SRM) Grain 5.13 %
0.25 lb Caramel/Crystal Malt -120L (120.0 SRM) Grain 2.56 %
0.75 oz Hallertauer [6.00 %] (60 min) Hops 16.6 IBU
0.50 oz Goldings, East Kent [4.00 %] (30 min) Hops 5.7 IBU
1.00 items Whirlfloc Tablet (Boil 10.0 min) Misc
2.00 items Cinnamon Stick (Boil 10.0 min) Misc
2.00 tsp Vanilla Extract (Secondary 5.0 min) Misc
2.50 tsp Pumpkin Pie Spice (Boil 10.0 min) Misc
1 Pkgs Nottingham (Danstar #-) Yeast-Ale



Beer Profile

Est Original Gravity: 1.049 SG
Measured Original Gravity: 1.045 SG
Est Final Gravity: 1.012 SG Measured Final Gravity: 1.014 SG
Estimated Alcohol by Vol: 4.87 % Actual Alcohol by Vol: 4.04 %
Bitterness: 22.3 IBU Calories: 200 cal/pint
Est Color: 15.1 SRM Color: Color


Mash Profile

Mash Name: Single Infusion, Medium Body, Batch Sparge Total Grain Weight: 9.75 lb
Sparge Water: 4.78 gal Grain Temperature: 72.0 F
Sparge Temperature: 168.0 F TunTemperature: 72.0 F
Adjust Temp for Equipment: TRUE Mash PH: 5.4 PH

Single Infusion, Medium Body, Batch Sparge Step Time Name Description Step Temp
60 min Mash In Add 12.19 qt of water at 170.1 F 154.0 F



Mash Notes: Simple single infusion mash for use with most modern well modified grains (about 95% of the time).
Carbonation and Storage

Carbonation Type: Corn Sugar Volumes of CO2: 2.7
Pressure/Weight: 5.0 oz Carbonation Used: 4.5 oz for 4.5 gallons
Keg/Bottling Temperature: 70.0 F Age for: 21.0 days


I have no idea what this flavor would come from. I have done other AG's since that have turned out great. Thoughts?

At first glance it may come from the vanilla, kinda a sweet aftertaste. I had a beer with vanilla in it and it tasted terrible. You didn't add all that much so I question how much of an impact that little amount would have. Nothing else in the recipe looks out of place.