I am about to start a Guinness brew this has to be one of my favourite drinks of all this , the recipe is a clone but it says to use food grade 88% lactic acid to your liking , it dose not say how much to use or when to add it . I think it means after fermentation or maybe when bottling , It says an easy less complicated way to slightly souring Guinness , So if there is anyone that brews Guinness or knows that can give me some tips would be a great help ,