pH data on souring milk
![](https://www.rogerfrost.com/wp-content/uploads/2018/10/image10.jpg)
The label on my milk bottle tells me how long the milk will ‘last’ at different temperatures. What do they measure to make this assessment? Is it the pH? I summoned patience, collected a glass of milk, pH electrode, pH sensor, data logger, data logger power supply and temperature sensor.
First run: leave the milk on a shelf above the heating radiator (about 29 degrees Celsius). The milk bottle label says that milk can be kept for a few hours at this temperature.
Insight file: milk_ph1.isa Excel or SID file: milk2.sid
Last run: leave the milk at room temperature in a heated room (about 21 degrees Celsius). The milk bottle label says that milk can be kept for half and day at this temperature.
Insight file: milk_ph2.isa Excel or SID file: milk2.sid
![](https://www.rogerfrost.com/wp-content/uploads/2018/10/graph-shots-free-datafiles-at-rogerfrost.com-04.jpg)