Single Step Infusion is the easiest of the mash regiments. The basic process is to add hot water to the mash tun and mix in the grist, do a mash out, lauter/sparge. This precess is pretty simple. The point in this process is to get the enzymes from the grains up to a happy temperature where they will start to convert the starches to sugars. The hot water is added so that the enzymes and starches are flooded out and are hydrolized, converting to sugars with just the one temperature rest. This rest temperature can vary depending on the amount of fermentable sugars desired (remember, rests at the lower in produce more simple, short chain sugars that more fully ferment, where rests at the higher end of the temperature range produce longer, more complex sugars that are less fermentable, building body and making the finished product sweeter rather than dryer). Once the conversion is complete, then a mash out temperature rest is preformed to denature the enzymes, setting the fermentability, and make the lautering process easier. The last step is to sparge the mash to rinse the remaining sugars out.
Lets look at an example single infusion mash.
If we assume a mash rest at 67 C (153 F), grist of 5 Kg (11 lbs) at room temperature (20 C, 68 F), grist ratio of 2.6L/Kg (1.25 qt/lbs) , and a pre-boil volume of 26L (6.7 gal), then:
1. Calculate the Strike Water Temperature. From John Palmer’s equation:
|Strike Temp = (0.41/grist ratio)(target temp – initial temp) + target temp
Strike Temp = (0.41/2.6)(67 – 20) + 67 = 74.4 C
|Strike Temp = (0.2/grist ratio)(target temp – initial temp) + target temp
Strike Temp = (0.2/1.25)(153 – 68) + 153 = 166.6 F
NOTE: You will have to understand your own system. This is a great calculation to get you in the ballpark, but different systems act differently and there can be varying temperature losses that can cause there numbers to be off in a real world situation. Take the temperature of the mash when you mix it and if its too hot you can add some ice, and if its too cold you can add some boiling water. Once you understand your system you will be able to start to account for these variances in your calculations. And remember to account to any additions of water in the rest of the calculations as needed.
2. Calculate the Strike Volume
Strike Volume = grist weight x grist ratio
Strike Volume = 5 Kg x 2.6L/Kg = 13L
Strike Volume = 11 lbs x 1.25 qt/lbs = 13.75 quarts (3.43 gal)
3. Bring 13L (13.75qt) of water to 74.4 C (166.6 F) and mix with grist in mash tun. Ensure there are no dough balls and the grains and water are mixed evenly. Leave until conversion is complete (about an hour or so, a bit longer for a cooler mash and a bit quicker with a warmer mash).
4. Infuse with boiling water to bring to mash out temp of 77 C (170 F). Once again, John Palmer’s equations:
|Infusion Volume = (target temp – initial temp)((0.41 x grist weight) + initial strike volume)/(infusion temp – target temp)
Infusion Volume = (77 – 67)((0.41 x 5) + 13)/(100 – 77) = 6.5L of boiling water
|Infusion Volume = (target temp – initial temp)((0.2 x grist weight) + initial strike volume)/(infusion temp – target temp)
Infusion Volume = (170 – 153)((0.2 x 11) + 13.75)/(212 – 170) = 6.45 quarts of boiling water
NOTE: This calculation assumed no temperature loss over the rest time and therefore leaves the initial temperature at the original rest temperature. In reality there is probably going to be a degree or so lost. When you are preparing the infusion you can take the temperature of the mash to understand this loss. Once you have worked with your system for a while you will probably have a good feel for how well it holds heat.
5. Mix infusion evenly to bring mash to mash out temperature and leave for about 10 minutes.
6. Start the runoff from the mash tun, preforming a vorlauf (recirculate the wort, about a couple of liters) to set the filter bed and clarify the wort running into the kettle. Run the now clear wort into the kettle.
If Fly Sparging:
7a. Have you hot liquor tank in place and filled with sparge water (at 77 degrees). Slowly run sparge water into the top of the grain bed at the same slow rate that the wort is running into the kettle. Continue until pre-boil volume is achieved to the wort running out is 1.008 or less (easiest to test using a refractometer).
If Batch Sparging:
7b. Calculate volume of sparge water needed (assuming 1.07L/Kg (0.51 qt/lbs) absorption by the grains, and a dead space in the mash tun of 1.5L (1.6 qts)):
Total Water Added = Initial Infusion + Mash Out
Total Water Lost = Water absorbed by grist + dead space loss
Sparge Volume = pre-boil volume – (total water added – total water lost)
Sparge Volume = pre-boil volume – ((Strike Water + Mash Out water) – ((absorption rate x grist weight) – dead space))
Sparge Volume = 26L – ((13L+6.5L) – ((1.07L/Kg x 5Kg) – 1.5L)) = 13.35L
Sparge Volume = 27.5 qt – ((13.75+6.45) – (0.51 qt/lbs x 11 lbs)) = 12.91 quarts
Once the trickle of wort is finished running out into the kettle, add the 13.35L of sparge water at 77 C, mix, vorlauf, and run out again.
8. Once the kettle is full, boil, ferment, package, and enjoy.