The NIST ytterbium-doped fiber laser used can provide up to 530 watts of laser output at a wavelength of 1.07 microns. At full power, they were able to deliver as much as 3.5 uN (0.35 mg) of force to the mirror. The experiments showed the expected linear relation between measured force and laser output.
It's just the way coffee is. Coffee is acidic. That's what probably upsets your stomach, especially if you're not eating or drinking other fluids throughout the day. People say that using coffee grounds are excellent for growing plants. BUT, they are only good for growing plants that are acidic soil loving plants.
1 The acidity of coffee is associated with digestive discomfort, indigestion, heart burn, GERD and dysbiosis (imbalances in your gut flora).  Addiction is often an issue with coffee drinkers and makes it really difficult to rely on the bodyâs natural source of energy.