Can not eating something be considered an offering?

I am currently somewhere where I cannot put food on an altar, nor can I pour libations other than water outside

I'm at a wedding and had asked Hera to watch over it and told her that while I didn't have something on me right in the moment, I would give an offering as thanks after the wedding

However the wedding is on a nature reserve so I can't just be tossing food or drink on the ground unless it's water

So I'm wondering if, while I'm eating something, if I just set part of the meal aside and don't touch it, could that "count" for lack of a better term? If I tell her, "This part is for you," and set it aside to not be eaten?

Or should I wait until I get back to my home state, to my altar, so I have a more designated space?