Each pack contains 50 indicator strips ranging from pH 4.6 - pH 6.2.
The best time to apply them is about 5 minutes into the mash. Just dip the swab strip into the mash for 2 seconds then remove it. Shake off any excess liquid. Compare against the colour chart.
When mashing, obtaining the correct pH level is important for optimum results. If the pH of the mash is wrong, your beer may develop off-flavours. However, if the pH balance is correct, your beer will achieve a better fermentation, better clarity and ultimately a better taste.
The optimum pH reading is between 5.0 and 5.4. The pH value of your mash may vary each time as it depends upon the water and the quantities and types of malt used. In most cases, the pH will be too high, so you will need to increase acid levels to achieve a pH reading of 5.0-5.4.