The way a proper perpetual stew works is that it never stops simmering and most solids should be eaten out of it within a day or two at most, essentially the ever boiling broth is the only true perpetual aspect. The reason medieval perpetual stew worked was because they where for large groups so all the meats and vegetables where quickly eaten, works a lot less when it's one dudes eating one bowl a day. Hes at least skim and straining it but if hes leaving meat and vegetables in it longer then a few days they'll eventually spoil and breakdown to a point it can't be fully strained out. Only skimmed the playlist but unless he just didnt mention it, it look like he wasn't straining it nearly enough, if he's not doing it every 3 days he might severely hurt him self.