Cold steeping dark grains is a great way of adding smooth clean flavor a to your porters and stouts without the risk of leaching tannins or disturbing your mash pH. First off, I think we should go into what cold steeping actually is. Most simply, cold steeping is the process of extracting the flavor and color of specialty grains through steeping in cold water.
Why Cold Steep?
There are two major reasons for cold steeping, Mash pH and Astringency. Dark, highly modified grains go through a very hot killing process. The effect of this roasting is not just flavor and color changes, but also changes in the chemical structure of the grain. Dark grains tend to lend more acidity to the mash. Now this is not always a bad thing, especially when brewing with highly alkaline (High pH) water. Unfortunately most water is relatively balanced in its pH. This means that the dark grains will bring your mash below the sweet spot of 5.2. This low pH will give your beer a very sharp character and will inhibit the enzymes of your mash. Cold steeping negates this issue by mashing only the base grains and light specialty malt; this way the mash is unaffected by the low pH grains.
The other aspect which makes cold brewing a useful tool is its ability to bypass the astringent aspect of roast grains. When exposed to hot water, dark grains tend to leach out acrid and astringent flavors. When cold steeping, the dark grains are exposed to no more than ten minutes of heat, and may even be exposed to no heat under certain conditions.
Cold Steep Process
There are numerous ways to conduct a cold steep. Experiment and see what process works best for you and your brew house. I have outlined my basic cold steeping process below.
1) Select your Grains: For the choice of grains, you want to stick with highly killed malt that will not require any heat to extract or convert sugars. At this point you just want color and flavor extraction. Good choices are black, black patent, special b, and chocolate malts.
2) Grind the Grains: If you don’t have access to your own mill, don’t worry about this step and go with the local homebrew shop’s mill setting. If you have control, go with a more coarse grind. Since you don’t have hulls to work with, clumping can be more of an issue so a more course grind will help prevent this issue.
3) Conduct the Steep: add the grains to your steeping bag. When it comes to the bag, bigger is better to allow more room for circulation in the steep. Fill a good grade bucket with 2 quarts of good quality water per pound of grain. Add the grain bag to the water and let steep over night, mixing occasionally to allow better extraction.
4) Remove the Grain Bag: Carefully remove the grain bag from the steeping liquid. It’s fine to squeeze the bag at this point, just try not to allow any husk material to enter the mix.
5) Add Cold Steep to Boil: With a minute left in the boil, add the steeping liquid. You should notice that the color changes dramatically when it is added. Stir gently till the mixture is well incorporated.
6) Finish the Brew Day as per normal.
Recipe: Chocolate Coffee Oatmeal Stout
This beer is based on a classic oatmeal stout but with some twists. Firstly it uses the cold steep technique for the chocolate malt and black printz. Secondly 3 shots of espresso were added at kegging to add a caffeine buzz. While this makes a very smooth beer, it is possible that the roasted flavors of a stout are lost in this recipe.
- 10 Lb Marris Otter
- 1 Lb Flaked Oats
- 0.75 Lb Chocolate Malt
- 0.75 Lb Black Printz
- 1.5 oz East Kent Golding – 60 Minutes
Mashed at 155 for 60 Minutes. Fermented at ambient temperatures.