Hi there, I have this problem where I get a very sore throat after drinking instant coffee, this can last for several days. I've tried various types of tea with the same results. So does anyone know what would be the best brand of coffee for my ongoing problem.

Perhaps a low acid instant coffee such as Kava brand? The only Low Acid Thai brand I see online here in Thailand is Kopiko L.A. but it’s a 3 in 1 that is loaded with sugar.

The Kava is available on eBay and some sellers ship to Thailand.

https://kavacoffee.com

& tea ... maybe you're allergic to caffiene

As much for a test of caffeine itself as anything:

Available for around 400 baht on Lazada. (Almost impossible to find in the stores). I keep some around to ward off the headaches from withdrawal symptoms when I couldn't get a cuppa because I was traveling in Asia. Not so much an issue any more with a coffee shop every 50' in Thailand and China where I travel. Still comes in handy in airports where even a lousy cuppa can cost $6-10.

At least you can self diagnose whether your problem is with the coffee, or just the caffeine.