
Gaskelling (verb). To deliberately underate, underplay oneself prior to a competition in order to garner extra sympathy votes or points.
October 2016 in preparation for Macc Homebrews Dark Beer Off, I decided to brew something that was a bit different.
I’ve tried to brew a potato lager before but unfortunately it became infected and tasted awful, and I’m adamant that I’ll brew a pale lager with potato again, but this time I wanted to brew something Autumnal. With every man and his dog dusting off the pumpkin ales I wondered whether sweet roast potato would taste nice in a beer, and with little more thought to it than that, I decided on a Roast Sweet Potato Stout, and despite it tasting overly fruity a week before the comp hence me negging my own beer, it actually came out OK and the verb Gaskelling was created.
Because this is a quite a big beer I’d recommend making a starter before hand which is detailed within the instructions.
unthought out (101)
Type: All Grain Batch Size: 23.00 l Boil Size: 27.41 l Boil Time: 60 min
End of Boil Vol: 25.52 l
Final Bottling Vol: 23.00 l
Fermentation: Ale, Two Stage
Equipment:
- 40l Mash tun with false bottom (helps stop grain flowing into kettle)
- 32l Kettle
- 10l Pan
- Sieve
- Measuring Jug.
- Digital Thermometer.
- Coiling Coil
- Hydrometer (optional).
- Assorted receptacles for ingredients.
- Fermenting Bucket and Airlock.
Ingredients
Amt | Name | Type | %/IBU |
3.70 kg | Lager Malt (Muntons) (3.0 SRM) | Grain | 42.2 % |
2.30 kg | Maris Otter Malt (Muntons) (3.0 SRM) | Grain | 26.2 % |
1.00 kg | Munich Malt (9.0 SRM) | Grain | 11.4 % |
0.50 kg | Caramel/Crystal Malt – 80L (80.0 SRM) | Grain | 5.7 % |
0.44 kg | Barley, Flaked (1.7 SRM) | Grain | 5.0 % |
0.42 kg | Carafa III (525.0 SRM) | Grain | 4.8 % |
0.28 kg | Caramunich Malt (56.0 SRM) | Grain | 3.2 % |
0.08 kg | Aromatic Malt (26.0 SRM) | Grain | 0.9 % |
1.50 kg | Sweet Potato (Mash 0.0 mins) | Spice | – |
66.20 g | Comet [9.50 %] – First Wort 60.0 min | Hop | 57.7 IBUs |
0.06 kg | Milk Sugar (Lactose) (0.0 SRM) | Sugar | 0.6 % |
1.50 kg | Sweet Potato (Mash mins) | Spice | – |
1.00 Items | Whirlfloc Tablet (Boil 15.0 mins) | Fining | – |
1.50 kg | Sweet Potato (Boil 60.0 mins) | Spice | – |
1.0 pkg | Abbey Ale (White Labs #WLP530) | yeast | – |
Prepare for Brewing
Create a yeast starter with 1.00 l of wort – typically this means adding 100gs of DME to 1l of water, bring to boil simmer for 15 mins, cool to pitching temperature, around 21c then pitch yeast. a good vessel for this is a 2l Erlenmeyer flask they come in a variety of sizes but are very handy. Cover the top with sanitised tin foil and aerate over a few days either with a stir plate, or by shaking when you remember to.
Brew time.
The first step with any brewing is to make sure your kit (and work area) is clean and free from any cleaning product residue.
Measure out all ingredients, splitting the ingredients into Mash and Boil
This Recipe calls for 1.5kg of Boiled and mashed sweet potato to be added into the Mash, and a further roasted crushed sweet potato to be added to the boil..
For this recipe we need to heat two lots of water at different times.
25.1 l Strike water that we add to the grain to create the mash. heated to 74.7c to create a mash temp of 65.6c
13.4l Sparge water heated to 75.6c to sparge the mash.
Need to boil and Mash 1.5 kg of sweet potato and also roast 1.5kg of sweet potato.
I’ll assume you know how to boil a potato, but in terms of the roast sweet potato, I pre heated the oven 200c and placed potatoes directly on the oven shelf with a tray underneath to catch leakage, after 45 mins or so I turned oven off and left potatoes in the oven until needed.
Mash or Steep Grains
Mash Ingredients
Amt | Name | Type | %/IBU |
3.70 kg | Lager Malt (Muntons) (3.0 SRM) | Grain | 42.2 % |
2.30 kg | Maris Otter Malt (Muntons) (3.0 SRM) | Grain | 26.2 % |
1.00 kg | Munich Malt (9.0 SRM) | Grain | 11.4 % |
0.50 kg | Caramel/Crystal Malt – 80L (80.0 SRM) | Grain | 5.7 % |
0.44 kg | Barley, Flaked (1.7 SRM) | Grain | 5.0 % |
0.42 kg | Carafa III (525.0 SRM) | Grain | 4.8 % |
0.28 kg | Caramunich Malt (56.0 SRM) | Grain | 3.2 % |
0.08 kg | Aromatic Malt (26.0 SRM) | Grain | 0.9 % |
1.50 kg | Sweet Potato (Mash 0.0 mins) | Spice | – |
I have no real idea how much additional fermentables are added when using sweet potato, but the process I used was to boil potatoes until mashable, the water used to boil potatoes was added to my kettle to help bring strike water up to temperature. The potatoes were then mashed with the skin on and allowed to cool then add to mashtun and mash in as normal.
The theory is that the 65c mash will convert anything the potato has to offer into fermentable sugars.
Mash Steps
Name | Description | Step Temperature | Step Time |
Mash In | Add 25.1 l of water to create a mash temp of | 65.6 C | 75 min |
This recipe calls for first wort hops so add all the hops to the kettle during sparge, this helps extract aroma from the hops as well as being more frugal with hops and achieving a smooth bitterness.
Fly sparge with 13.41 l water at 75.6 C
Add water to achieve boil volume of 27.41 l
Estimated pre-boil gravity is 1.074 SG
Boil Ingredients
Amt | Name | Type | %/IBU |
66.20 g | Comet [9.50 %] – First Wort 60.0 min | Hop | 57.7 IBUs |
1.50 kg | Sweet Potato (Boil 60.0 mins) | Spice | – |
1.00 Items | Whirlfloc Tablet (Boil 15.0 mins) | Fining | – |
For the last 15mins of the boil add in protofloc and copper coil
Estimated Post Boil Vol: 25.52 l and Est Post Boil Gravity: 1.082 SG
Cool and Transfer Wort
Cool wort to fermentation temperature
Transfer wort to fermenter
Add water if needed to achieve final volume of 23.00 l
Pitch Yeast and Measure Gravity and Volume
Fermentation Ingredients
Amt | Name | Type | %/IBU |
1.0 pkg | Abbey Ale (White Labs #WLP530) [35.… | Yeast | – |
Once fermentation has completed take reading then add
0.06 kg | Milk Sugar (Lactose) (0.0 SRM) | Sugar | 0.6 % |
Target: 1.082 SG)
(Target: 23.00 l)
Fermentation
Primary Fermentation (4.00 days at 19.4 C ending at 19.4 C)
Secondary Fermentation (10.00 days at 20 C ending at 20 C)
Cold crash 3c for 20 days
Bottling or kegging
Typically I add 1/3 teaspoon of sugar to 330ml bottle or 1/2 teaspoon to 500ml bottles.
Kegging is done at around 14psi and 7c
This beer didn’t win the dark beer off.