If you want to thicken a chili, the best way is to put a couple of tablespoons of flour or cornstarch in a pot and slowly stir in enough liquid – water is preferable – to make a slurry.
Mix well with a whisk, then pour this mixture into the soup by the spoonful as if you were adding stock. The liquid will begin to thicken as it cooks.
If you plan to add a roux (a mixture of flour and butter), wait until the end before you do.
If you are planning to use any other thickener , mix it with an equal amount of cold water, then stir this into your soup by the spoonful as if it were stock.
The best way to remove lumps from a hot mince mixture is to put it in the refrigerator for about 30 minutes after you have mixed everything together.
This allows the mince to congeal slightly, making any lumps easier to remove before sautéing .
A little bit of butter added when cooking vegetables will help them retain their color.
So this is how to thicken Chili.