This is important. Weigh the jar and write the number down. Don't be like me and not. Then you'll just be a few minutes later like a dumbass and have to empty the thing out and it's just a mess. Just write it down please.
Now, we sterilize the jar, or thereabout. We put it into the sink and pour scolding hot water into it all the way to the top. Pour some into the lid as well. Let it stand for a few minutes before you empty it out. Watch out it will be, well, scolding hot.
Now down to business. I start with rinsing the chilies in a bowl with water and a little vinegar then rinsing them off. Cut them into about 2 cm (inch) large pieces. Put them into the jar seeds and all if you like our hot sauce hot, if not you're an idiot. Just kidding, Then just hold back some or all of the seeds (I dry them an keep them for planting next season - waist not want not).
Peel the garlic and slice finely. The more surface area the more flavor. Put them as well as the sugar (if using), peppercorns and cardamom seeds into the jar as well.
Pour water into the jar until you cover the chilies not minding if they float a little, you'll weigh them down in a minute. Leave a few cm (a couple of inches) headroom in the jar.
Now for the fun process of mathematics in cooking. I'll first iterate how very very important this step is. When we ferment we have to make sure that we create an environment where good bacteria can work their magic and where the bad cannot. This is why we use a calculator and scale in fermentation.
Weigh the jar plus all ingredients. Remember the number you weren't going to write down because it was so easy to remember? Right? Glad you decided to follow the instructions and write it down. Now, deduct the weight of the jar from the total weight.
The number you are left with is the total weight of all your ingredients. You need then to multiply this number with 0,03 to get 3% of that total weight. Confused yet? I'll give you an example if your total weight is 1500g then the math is 1500x0,03=45. This means you need 45g of salt. (If the total weight is 50 ounces then the math is 50x0,03=1,5 ounces of salt.
What I do next is pour most of the water from the jar into a bowl and add the salt mixing well, before I pour it back into the jar. I seal the jar tightly and shake it a bit mixing the ingredients well.
At this point you should se that the chilies have a tendency to float rather then stay submerged. This is less then desirable because this exposes them to oxygen and increases the likelihood that they will go bad. What you want here is to find something you can weigh them down with. I use a clear plastic bag that I put about a half a cup to a cup of water into and tie off. Then I gently place it inside the jar making sure all the chilies are submerged.
Don't screw the lid all the way just lightly close it making sure the excess gases from the jar can escape. If you don't, or are using a clip on lid, make sure you "burp" the jar at least once a day (I would do it more often). Label the jar with both what is in it and date, and leave it out to ferment.
Now it's just a waiting game. Leave it out on a shelf or a countertop to ferment for 5 to 14 days. you can taste occasionally to see if it has the level of fermentation you want.
It's all done fermenting to your specific liking? Good. Now you strain off the liquid, but hold on, don't throw that liquid gold away. You'll need some of it in your hot sauce and the rest you should keep it and use it as a condiment in itself, on fries, grilled meat, etc.
Throw the rest into a blender and blitz it into oblivion. Pour small amounts of the brine into the blender until everything comes together. If you want you can add a little vinegar and/or salt to taste. Strain the sauce, don't strain, I really don't care and it is your hot sauce so it's totally up to you.
Pour it into a bottle or keep it in a jar in the fridge because it will keep fermenting if you don't.