The same is true if before Yom Tov wine was left in the vat after being pressed and then you became an avel before you could finish processing the wine. Now that it is Chol Hamoed you can complete the process as usual. . This is also true if some other uncontrollable circumstances occur to stop the processing from completing before Yom Tov such as the workers stopped working right before Yom Tov. R’ Yehuda says you can just put a board on top of the barrel so it won’t get ruined but you cannot seal it.

Moed Katan 2:3

You can bring in a lot of fruit from the fields, if it might get stolen. You can take out soaking flax so it should not get ruined. All these can be done as long as you don’t intentionally leave it to be done on Chol Hamoed. If you did leave it to be done on Choil Hamoed, then you lose whatever you did.