pH – Surface, Cold Extraction and Hot Extraction Play Video VIEW PH SURFACE ONE-SHEET To view this document, you may need Adobe Reader or Adobe Acrobat. PH – SURFACE, COLD EXTRACTION AND HOT EXTRACTIONWe measure surface pH according TAPPI test method T529. A drop of distilled water is placed on the surface to be tested, either coated or uncoated. A surface pH probe is placed on top of the drop and allowed to equilibrate for five minutes. At the end of five minutes the pH of the wetted surface is recorded.We also measure cold extraction pH according to TAPPI test method T509 and hot extraction pH according to TAPPI test method T435.