When Sims take the Final Exam there is a random Loot where they cheat and either fail or succeed at cheating. Every Sim that is not at least lvl 4 in Mischief has a high Chance to fail and get caught. I changed the random loot a bit: Only Sims with at least level 6 in Mischief should cheat and only have a chance to fail when they have the Clumsy Trait.
This is a an ingredient that can be used in my other custom recipes and can be purchased from my Brazen Delivery service if you don't want to craft it. This includes a recipe that will allow your sim to create a barrel of vinegar mash from my Preserving Shelf or the Brazen Homestead Craftbooks. Once created, that barrel can be aged and vinegar can be collected from it at different stages. That can then be used as an ingredient in other recipes.