Halacha (law), Gimel (three). Let's say you have fruit that has partly ripened and is edible. You can pick it from the fields and haul it away to eat. Let's say you pick it in order to eat it, and there are leftovers. If you're worried that, if you leave them, they're going to get wormy, you want to press them to take out the moisture, and you can press them. You cannot pick the fruit knowing there is any extra, with the intention of pressing the extra fruit. But let's say if you're not going to find these fruit after the Moed (festival), you can buy an excess amount and just press the rest from the beginning.
The source of what you have is like business: let's say the price is going to go up, or you're not going to be able to find the item after Chol HaMoed (the intermediate festival days). Therefore, if I do this over here, even though you're going to buy them to press them, you're buying stuff here and pressing it. For sure, you cannot benefit from Chol HaMoed. The religion is not for Chol HaMoed.