Pour the grain into Cold Water
Start by collecting water in a bucket of some sort, and be prepared to cool it to around 5°C/41°F (fridge temp). I pour my milled grains into a BIAB (Brew In A Bag). I dont adjust water chemistry at this point.
Non-Enzymatic Mash (NEM) / Cold Mash.
New and Proven Brewing Techniques. Familiar but different.
Fig 1. Recovery of malts components using a 24-hour cold extraction process compared to Congress Wort.1 *Soluble Nitrogen and Beta Glucan not assessed for this malt type. https://www.brewingwithbriess.com/blog/cold-extraction-of-malt-components-and-their-use-in-brewing-applications/
Below is a general guide on how to brew a NEM (Non-Enzymatic Mash) otherwise known as a cold mash. The reason we use this is to capture colour, flavour, and mouthfeel from malts, while limiting the extraction of complex carbohydrates. In other words, we drop out the starch and remove it before fermentation so that the yeast has less sugar to eat and convert into alcohol.
I use Brewfather for all my brewing tools and to create my recipe’s, but you may use your desired program/software. I find that when I am doing a NEM batch, if I drop my brew-house efficiency to 20-25% and reduce my hop additions to half (low alcohol beers need to observe BU/GU ratio’s be reduce perceived bitterness) this gives me good results. I also hotcube and offset my hop editions by 20 minutes and / or whirlpool editions or I overshoot my IBU’s and end up with a beer that’s too bitter.
– Ben
Stir the grains into 5°C/41°F water
I give it a good stir to break up any dough balls.
Secure BIAB and Lid
Give it a good spray with sanitiser and put the lid on securely.
Place in Fridge for a minimum of 8 hours at 5°C/41°F
Put in the fridge at around 5°C/41°F for about 12 hours/overnight.
Pour off wort into second bucket
Pour off the top into a 25 Litre hotcube (or similar) which has a tap on the bottom. I don’t tilt the container and I ensure that I leave all of the starch sediment I can in the bottom of container 1.
Don't squeeze the bag
Take the lid off and get it ready to lift the bag. Do not squeeze the bag. It will add a grainy, worty flavour.
raise bag
Lift the BIAB with a pully. Do not squeeze or disrupt the grain. This will fill the Hotcube with clean, un-sedemented wort.
You dont have to sparge, its a personal preference and a useful way to make up water level.
Racked Wort Rest
If I sparge, I Leave the hotcube to sit in the fridge, or on the bench, for another 2 hours. The hotcube has around 2 Litres of dead space under the tap and this will fill with sediment again. You must remove this or it will scorch your kettle.
This step is not entirely necessary if you are careful enough the first time to not disrupt the wort.
Mash
Once all the sediment is removed I heat the wort to mash temp, put in my bag of grains, add my water chemistry and mash at 80ºc.
This can be done in a pot on the stove if you dont have a brew kettle.
Boil
I sometimes boil or sometimes I just do a 90ºc hopstand and add my bittering hops, whirlfloc, Yeast nutrient. It depends of the beer style.
After boil/hopstand I pour the hot wort into a HDPE hotcube and leave it overnight for future fermenting.
– NEM Demonstration by Ben