The Saviour schnapps allows you to save your game whenever you want in Kingdom Come: Deliverance, the alternative consisting in relying exclusively on auto save, which does not always come at the best of times…
First, you will need a few basic ingredients that you will be able to find in the nature or at an apothecary’s:
Approach an alchemist’s lab (available in every sizeable town), interact with it and open your inventory to select your ingredients.
Then look to your left to get some wine (second jar from the left) and pour it into the cauldron. Use the bellows to light the fire.
Get the nettle on the shelf to your right, put it directly into the cauldron and use the bellows twice.
Then the two belladonnas go into the mortar, right in front of the cauldron. Use the mortar to crush the whole thing.
Drop the contents of the mortar into the cauldron, use the bellows one last time then interact with the array of potions on the left, between the bellows and the jars.
Use the cauldron with the potion in hand. A good ol’ Saviour’s schnapps to enjoy in peace and quiet.