NBAP

"Acceptable," he said. "Do you mind if I have a sip of that potion?"

Clearly, Harry is in need of the potion, if he thinks this is an acceptable suggestion.

That's good. Apologies for (facetiously, admittedly) passing judgment without being fully aware of the details of the project.

Worth noting, perhaps, is that the main reason people fail to open jars is not due to a lack of grip strength, but due to a lack of friction. If you have a stubborn jar that you cannot open, put on a pair of rubber dish gloves and try again, and I think you'll be surprised at how easily a previously-unopenable jar magically pops open. This method has literally never failed me.