You sit down to eat, you get the aroma of your favorite mealtime dish, you are ready to chow down and something begins to happen in your mouth. You begin to salivate. This is a reflection of the enzyme amylase kicking in for the starch digestion process. This enzyme needs a range of pH ideally around 7.2 pH. So if you have adequate alkaline reserves in your body, testing your saliva pH as you salivate before a meal should give you a pH reading of around 7.2. If your pH is not getting up to at least 7.0, you can assume there is stress in your alkaline reserves and the further below 7 it goes, the more depleted are those reserves. You could also suspect digestion all around is not doing so well. This typically indicates a longer term problem and more serious effort needs to be applied to help  restore overall health.