I can all be done with simple math, but I think it would be cool if this forum had a guide on how much gold each factory and animals produce. Please notice I'm not taking the consideration the time to harvest the ingredients, in most of the cases that time becomes doesn't matter much cause you can stock them beforehand or grow them by the time the factory still working. I'm making some approximations too. In the final sum I'm still considering the money to pay for the ingredients though. You can view another guide also here by Akachan-chan!
Equation: (60 minutes)/(time it takes to produce something)x(selling price) - (60 minutes)/(time it takes to produce something)x(cost of the crops)
Bread Factory 490g/h This factory will take 2h to pay itself start generating profit
Butter factory 380g/h This factory will take 3h 12m to pay itself start generating profit
Apple Vinegar 200g/h (only if you have 10 threes, or a lot of stocked apples. With just one this can get low as 20g/h) This factory will take 7h 30m to pay itself start generating profit
Ketchup 221g/h This factory will take 8h 6m to pay itself start generating profit
Orange Juice200g/h (this value also can get a lot lower if you don't have enough threes) This factory will take 11h 20m to pay itself start generating profit
Strawberry Milk 245g/h This factory will take 10h 12m to pay itself start generating profit
Sausage 226g/h This factory will take 17h 40m to pay itself start generating profit
Cookie255g/h This factory will take 23h 30m to pay itself start generating profit
Tofu235g/h This factory will take 42h 50m to pay itself start generating profit
Popcorn 230g/h This factory will take 63h to pay itself start generating profit
Olive Oil180g/h (and possibly way less if you don't have many threes) This factory will take 108h to pay itself start generating profit (please tell I did the math wrong cause, damn, that's a bad deal)
Chocolate 324g/h This factory will take 115h to pay itself start generating profit
Yarn 333g/h This factory will take 120h to pay itself start generating profit
Apple Sauce 441g/h This factory will take 120h to pay itself start generating profit
Cow180g/h
This animal will take 5h to pay itself start generating profit
Hen120g/h This animal will take 10h to pay itself start generating profit
Pig210g/h This animal will take 12h to pay itself start generating profit
Bee125g/h This animal will take 40h to pay itself start generating profit
Bull260g/h
This animal will take 115h to pay itself start generating profit
Thanks to lovely Elynai! Please correct me if the math is wrong and feel completely free to post things to add to the guide!