Water and oil don't mix, that's common knowledge.

What about essential oils though?

They are a bit different...

For example, cook an orange peel it will give flavor, same with ginger or herbal teas.

They all contain it.

Unless there are some lechitins present in the plants I have no explanation how.

Which brings me to my question.

In HOT or BOILING water, would it be soluble?

If yes, this is a great way to flavor drinks with food grade essential oils.

Anybody some thoughts, experiences or theories on that?

Detailed study reports could also be helpful.

most essential oils are by 80% terpenoids, terpenoids are high non-polar molecules, and have very low solubility in water, around 0.005−0.030 mg/mL, so essential oils are considered hydrophobic.

The reason why you can flavor foods with them is because they typically have intense odours. Thus the amount thay dissolve, diffuse or disperse into food is quite sufficient to produce a detectable aroma. As you partly observed, foods generally contain other componrnt which aid the dispersion of the essentialoils.

In the case of plain hot water the situation depends on the oil concerned, as the exact chemical nature of each of its components impacts the solubility and the temperature/solubility curve. Herbal teas will contain additional components which may increase the solubility of essential oils on accoint of the plant material from which they are produced.

Maybe you are lucky with some essential oils whose terpenes have a crazily strong smell

Just for fun I put some Limonene drops into a pot of boiling water, now kept boiling for 10 min and then just took some water with a pipette - making sure that I did not fetch any REAL limonene from the surface (was very easy, as I just have like 4-5 droplets on a 1 L volume of water, so no "cross contamination" )

Now I think this 1 ml does not have any real smell? So as DF0 said maybe adding some emulgator would help, from simple washing soap (which will carry perfume on its own ...) to bio-based molecules like Lecitin there might be a broad spectrum which could help?

emulgator = emulsifier

Do you have any specific plans for particular essential oils? I'm sure there's a decent amount of recipes & information to be found by searching through various culinary websites.