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.
All coffee beans contain an enzyme that's a strong GI irritant. This can cause painful spasms, urgency, and diarrhea in people who don't even have IBS. Imagine what it can do to you. This is true for regular and decaf, instant or freshly ground, espressos, lattes, and a plain cuppa Joe. Coffee is also highly acidic, which can aggravate upper GI issues such as reflux or heartburn.