There are a couple of things you will need before you can start on thi journey. Firstly you will need a brewing system or method in which to brew. You can use any all-in-one system including those with or without circulation. The important thing here is that whatever you use is suitable to be held at temperature for 48 hours.
Secondly, you will also need a device for measuring PH with good accuracy. You should definitely use a PH meter. Also, you will need something in form of a chemical that can be used for lowering your Ph. Calcium sulfate or chloride are popular choices as well as food-grade lactic acid. Add something to sour your wort with. There are various choices. Additions that are designed for the process and measured offer an advantage in terms of reliability and a controlled result. The last things you will need are your recipe ingredients and something to ferment in. For more info on sour beer brewing check our Sour Beer Brewing Part 1
Step 1 – The mash
Mash in your grain and perform a normal mash according to your recipe. We recommend that you also perform a mash-out step to prepare for sparging.
Step 2 – Sparge
If applicable to your brewing method is to perform a sparge.
Step 3 – A 5-minute boil
Heat up to a boil and hold the boil for 5 minutes to sanitize. You can use some of this time to clean the protein on top by stirring it in. Not only does this avoid a boil-over but also keeps the protein in the beer rather than removing it.
Step 4 – Wort Chilling to 95 F
Chill your wort down to 95 F. This is faster done using an immersion chiller.
Step 5 – Pre acidify to PH 4.5
Pre acidify using your chemical of choice down to PH of 4.5. It is very beneficial in protecting against other unwanted bacteria and also reduces potential Lacto activity that can work against head retention and the body of your beer.
Step 6 – Add your bacteria
Add your bacteria of choice.
Step 7 – Oxygen protection
Add in some oxygen protection. There are various methods of this. A good beginner method is to add clean and sanitary cellophane to the top of your wort. Sealing it in on the sides of your kettle.
Step 8 – The Souring
This process can take 24 to 48 hours in actual fact. But we opted for 48 hours to obtain greater complexity. The souring process is complete once you have a PH of between 3.4 to 3.6. Which is a simple question of taste.
Step 9 – Finish the brew as normal
Finish your brewing process by boiling and adding in your hop additions according to your recipe. Hops at this point will have no effect on your bacteria. Cool and add to your fermenter as usual. Your choice of yeast needs to be one that will be tolerant of a low PH. Cheers.