Can we eat and drink the offerings made to spirits?
Please use the search function. This question has been asked and answered many times.
In a word, yes. Been asked many time and this is the consensus, also it’s normal for Hindu offering, they are always shared in a feast afterwards.
Having that that, I don’t do it. To me the essence of the food has gone and that’s what I actually want out of the food myself, so there’s no point eating it. It also kinda feels like I made the offering fake.
I would say, if you really offer something that feels like a loss to not eat it afterward, you have moved into the territory of making a sacrifice, and at that point the energy is even stronger and you definitely don’t want to eat it as that eliminates the sacrifice.
If a spirit is invoked, especially to extreme degrees (e. g. possession) I believe yes.
I normally bury them beneath a tree in my garden, just one time, I offered some truffles to the goddess and at the end of the ritual when I was picking up everything and reached the candies I heard a voice saying “Half”, she asked me to eat the half of the truffle so I did. .
Gordon Winterfield explains his perspective on this very well in his book Demons of Magick. He describes it as the offering being a sharing of the experience with the spirit.
Say if your offering is a glass of wine. You would call in the spirit and invite it to share your subjective experience of it through you. You would drink it slowly, taking time notice and savour the flavours and textures and any other aspect of the experience, whilst keeping in your mind the intention of sharing that experience with the spirit.
If I’m not calling the spirit into me I’ll leave it on the offering spot so the spirit can take the “ka” or energy out of the food gradually from the altar.
If I invoke the spirit to the point of possession then I believe it’s more respectful to allow the spirit to experience the food thru you and enjoy the human sensations they crave using your body, it’s sensations and experience 
It depends on the nature and the tradition of a spirit… Or the context.
Some spirits (like faes) needs their own serving, then you have to properly dispose it.
It can also depends on the nature of the spirit. If it’s about to attract or banish.
Just remember than the spirit is going to eat the ether.
Unless the food isn’t fresh anymore I wouldn’t eat it but good bourbon after being infused and blessed by our blessed gods SHOULD never be wasted and enjoyed thoroughly.
Personally, I’ve been in situations where food has been scarce and I know it has something to do with my upbringing that makes me think like this but the idea of tossing out food has just never sat right with me. I know that in some cases the spirit requires it but with me it always feels like I’m wasting good food at times when there isn’t much to really spare. This feeling on top of my previous living situations, like way out in the boonies - it can be dangerous to toss out food, especially if it’s within spitting distance of your home because the smell has the very strong possibility to attract wildlife.
You never wanna be the one to walk out your front door to a hungry bear poking around because you tossed or buried something maybe a lil too close to home, or a troop of coons waiting to ambush you for scraps (better than the bear imo).
My way around it is I allow the spirit to experience the taste of the food through my body, I eat slower and savor every bite giving the energy to them through me…like a conduit. They get the energy of the offering and get the human experience of eating, I get guilt free sustenance all with no waste or worry. If you’re going this route than the meal from start to finish should be one solid devotional act, make a ritual out of it.
EDIT TO ADD: Typically if you’re working with a spirit they won’t be unreasonable when it comes to your circumstances, and what you realistically can and can’t do. If they are than I’d take a second to really consider weather or not this spirit truly has your best interests in mind.
I always do so. I tell them to experience the food/drink through me.