I have had a few really terrible homebrew versions of a coffee porter and coffee stout. All of them had the same thing in common, the brewer would make a pot of coffee and dump it in at some point during the process. This would cause the beer to be very astringent and acidic due to the acid pulled from the coffee beans during the coffee brewing. One method to circumvent this is to make cold press coffee which is the process of combining cold water and coffee grounds and letting it steep 24 hours in the refrigerator. Here is the exact process I used:
Sanitize a quart mason jar. Add 12oz of filtered cold water and 2T of freshly coarse-ground coffee beans. Shake to combine and place in the refrigerator for 24 hours. Strain through a coffee filter to seperate the grounds from the liquid. I added this at flame out or you can add it to secondary.
I followed the guidelines for a Robust Porter style:
Ingredients:
Malt -
7lb - Riverbend Heritage 6-row Malt
2lb - Munich Malt
1lb - Crystal 120 Malt
0.5lb - Victory Malt
0.25lb - Carafa III
3oz - Acid Malt
1lb - Corn Sugar
Hops -
1.5oz UK Fuggles (3.6% AA) @ 90 min
1oz UK Fuggles (3.6% AA) @ 60 min
Water Prep:
My water has a very low mineral profile so I wanted to shoot for more of an English water profile. The addition of the 3oz of Acid Malt should also lower my mash pH to 5.3 which is my target for brewing a darker beer.
Strike Water -
1g - Calcium Chloride
1g - Gypsum
Sparge Water -
1.5g - Calcium Chloride
1.5g - Gypsum
Mash @ 154F for 60 min and boil for 90 min. I have started to do all of my boils for 90 min just to reduce the risk of having DMS.
Ferment with Wyeast 1056 @ 66F
Measured OG - 1.055
I did seem to miss my mark on the pH of the mash. I got busy with something else and did not check the mash at 30 min so I checked it at 50 min and the measured pH was 5.26 which was very low from my target of 5.3 pH with the EZ Water calculator. I am thinking the Riverbend Heritage malt is the cause of the miscalculation as it has a higher SRM than a traditional base 6-row malt.
11/18/2013 - Update:
Measured FG - 1.009
ABV 6.1%
The finished beer turned out ok but not great. It has a slight bitter after-taste, the same type of bitterness you would encounter in a fruit pit such as a peach. The coffee flavor is present but not overpowering, the bitterness is just too much to really get a grasp on the intricate flavors of the coffee. The next time I will back off on the Crystal 120 and add some lighter crystal to balance out the flavor and not add the Gypsum. I will also use a more robust coffee and up the amount to bring out more of the coffee notes.
