All Oat Bitter/Keptinis

160 calories 14.3 g
Beer Stats
Method: All Grain
Style: Strong Bitter
Boil Time: 60 min
Batch Size: 2.5 gallons (fermentor volume)
Pre Boil Size: 3.75 gallons
Post Boil Size: 2.8 gallons
Pre Boil Gravity: 1.037 (recipe based estimate)
Efficiency: 55% (brew house)
Calories: 160 calories (Per )
Carbs: 14.3 g (Per )
Created Tuesday August 11th 2020
Amount Fermentable Cost PPG °L Bill %
8 lb United Kingdom - Oat Malt8 lb Oat Malt 28 2 100%
8 lbs / 0.00
Amount Variety Cost Type AA Use Time IBU Bill %
0.15 oz Centennial0.15 oz Centennial Hops Pellet 10 Boil at 180 °F 60 min 12.84 7%
0.50 oz Fuggles0.5 oz Fuggles Hops Pellet 4.5 Boil 15 min 9.56 23.3%
0.50 oz BSG - East Kent Goldings0.5 oz East Kent Goldings Hops Pellet 5.3 Boil 15 min 11.26 23.3%
0.50 oz Fuggles0.5 oz Fuggles Hops Pellet 4.5 Boil 5 min 3.84 23.3%
0.50 oz BSG - East Kent Goldings0.5 oz East Kent Goldings Hops Pellet 5.3 Boil 5 min 4.52 23.3%
2.15 oz / 0.00
Mash Guidelines
Amount Description Type Temp Time
2 gal Strike 152 °F 60 min
3.75 gal Sparge -- --
Starting Mash Thickness: 1 qt/lb
Other Ingredients
Amount Name Cost Type Use Time
0.25 g camden tab Water Agt Other 0 min.
8 g Fermaid O Other Primary 0 min.
1 each Whirlfloc Water Agt Boil 10 min.
1 tsp Amylase Powder Water Agt Mash 0 min.
2 g Calcium Chloride (anhydrous) Water Agt Mash 1 hr.
2.50 g Gypsum Water Agt Mash 1 hr.
1 g Baking Soda Water Agt Mash 1 hr.
37.21 ml Phosphoric acid Water Agt Mash 1 hr.
14.37 g Phosphoric acid Water Agt Sparge 0 min.
1 Each
Attenuation (avg):
Optimum Temp:
77 - 104 °F
Fermentation Temp:
Pitch Rate:
0.35 (M cells / ml / ° P) 40 B cells required
0.00 Yeast Pitch Rate and Starter Calculator
CO2 Level: 2.25 Volumes
Target Water Profile
Balanced Profile
Ca+2 Mg+2 Na+ Cl- SO4-2 HCO3-
80 5 25 75 80 100
Mash Chemistry and Brewing Water Calculator

Plan is to bake portions of the mash (like the keptinis descriped here: to achieve a darker wort and more complex flavor.


Some results and lessons learned:

  1. While the mash converted, eventually, as evidenced by an iodine test, I have the feeling it was mostly larger unfermentable dextrines. While the wort was sweet, it definitely wasn't as sweet as I would have expected. When I baked the mash I got plenty of browning, some burning, but little actual caramelization - my Chemistry-fu is weak (something I should correct one of these days), but that seems like it would be indicative of more maillard reactions than caramelization. Finally, the Voss I pitched (@102f, held at 95f for the duration) chewed through the wort to 1.020 in just a few hours (lag time was maybe 45m), and then stuck there solidly. Next time, mashing with some glucoamylase alongside the alpha amylase might be in order. If only I could find some enzymatic oat malt...

  2. In retrospect, a step mash would probably be appropriate here; the oat malt is almost certainly under modified, and dealing with some of the beta-glucans would be a good idea. Next time, maybe rests at 113 and 122 would be a good idea?

  3. When baking the mash, I preheated the oven to 500f (with several baking stones on the bottom for thermal mass), before turning it down to 380f with convection right as I put the mash in. The mash itself was split between two aluminum roasting pans, a pyrex baking bowl, and a cookie tray, and baked for about two hours. While the mash in the roasting pans thickened and browned nicely, albeit with less caramelization than I had hoped for, the cookie tray just burned and the baking bowl remained fairly liquid inside. Roasting pans all the way next time.

  4. Next time I need to remember to allow the yeast more time to clean up; by the time I check the next morning, after brew day, this had already reached it's terminal gravity of 1.020, so I allowed it 24 hours to make sure it wasn't going to move, and then cold crashed. That was almost certainly too fast, even for kviek.

  5. Results: the pre-carb sample I pulled, after closed transfer to a serving keg, wasn't bad. The beer evidenced some harsh burnt toast flavors, but it seemed like it would be drinkable, especially after a little bit of mellowing with age. After a few days force carbing though, it developed a highly medicinal, hard to describe, backtaste - perhaps the carbonation just made some compounds (phenols?) more accessible to taste, or maybe I got an infection during the transfer or in the new keg? I'm going to let this keg hang around at room temperature for a few weeks before tossing it, on the off chance those flavors clear up, but I don't have high hopes.
View Count: 161
Brew Count: 1
Last Updated: 2020-08-24 18:28 UTC

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