I have to admit I have never tried the cayenne in water, don't think I could do it. I encapsulate the cayenne and usually take two '00' caps at a time with lots of water or fluids. If I don't drink enough water, I tend to get indigestion for a short time.
Dr. John R. Christopher was a staunch believer in cayenne. Following is from his Aliments CD put out by the School of Natural Healing (which he founded).
Fruit (oil is in the seeds).
Stimulant, tonic, carminative, sialagogue, stomachic, rubefacient, pungent, alterative, astringent, antispasmodic, sudorific, emetic, antiseptic, condiment, anti-rheumatic.
Cayenne is a medicinal and nutritional herb. It is the purest and most certain stimulant.
This herb is a great food for the circulatory system in that it feeds the necessary elements into the cell structure of the arteries, veins and capillaries so that these regain the elasticity of youth again, and the blood pressure adjusts itself to normal. It rebuilds the tissue in the stomach and heals stomach and intestinal ulcers; in equalizing the blood circulation, cayenne produces natural warmth; and in stimulating the peristaltic motion of the intestines, it aids in assimilation and elimination.
When the venous structure becomes loaded with sticky mucus, the blood has a harder time circulating; therefore, higher pressure forces the liquid through. Cayenne regulates the flow of blood from the head to the feet so that it is equalized; it influences the heart immediately, then gradually extends its effects to the arteries, capillaries, and nerves (the frequency of the pulse is not increased, but is given more power).
Apoplexy, arrest gangrene or mortification, arthritis, asthma, asthmatic asphyxia, atonic gout, bleeding, bleeding of the lungs, chilblains, chills, colds, cold extremities, congestion, constipation, cough, cramps, debility, delirium tremens, diphtheria, dyspepsia, emesis (strong dose), functional sluggishness, fatigue, heart trouble and heart attacks, hemorrhage, hemorrhoids, high and low blood pressure, indigestion, inflammation, kidney and related problems, lethargy, low fevers, lumbago, menorrhagia, neuralgia, offensive breath, pains in the stomach and bowels, palpitation, pleurisy, profound shock, quinsy, rheumatism, scarlet fever, strokes, tonsillitis, toothache (oil), typhoid fever, ulcers, vomiting, wounds, yellow fever. Cayenne (as a stimulant) is an activator, carrier, and accentuator.
Hope this helps,