In the brewing process, the enzymes required to convert the starch into sugar are pH-sensitive with an optimal pH range between 5.2 pH and 5.6 pH. Different compounds are used to adjust the pH including phosphoric acid, lactic acid, and gypsum.
Wort clarity and break formation are also affected by pH. Protein coagulation occurs during wort boiling, where the optimum pH is around 4.9, even though a common boil pH is 5.2. A pH that is too high will not only inhibit coagulation but also promote browning due to the interaction of amino acids and reducing sugars.
Hop utilization during the wort boil is also affected by pH. As pH increases, the solubility of hop resins increases. Unfortunately for hop lovers, a high pH also increases the release of tannins resulting in a harsher taste. Higher pH also favors elevated microbial activity.
As a living catalyst, yeast maintains a pH around 6.5 within its cells; however, the preference is to inhabit a more acidic environment. During the fermentation stage, the pH should be lower to accommodate the yeast and also to ensure microbial stability and consistent flavoring of the beer; an optimal pH range during fermentation is between pH 4.1 and 4.3.
The HI99151 uses the FC214D amplified pH electrode with titanium body. This specialized electrode offers numerous features that improve pH testing in beer. An integrated temperature sensor allows for temperature compensated pH measurements without the need for a separate temperature probe. The probe’s spheric sensing tip has a wide surface area for measurement in aqueous solutions.
A typical pH electrode has a junction made of cloth material. This cloth material can be easily clogged by samples such as mash, which has a high solids content, or wort, which is viscous. With the cloth junction of the FC214D it is possible to clear any obstruction by simply extracting 1/8” of the junction from the electrode. This exposes a new, renewed portion.
Titanium construction provides an unbreakable structure and allows the transfer of heat to the internal temperature sensor for rapid temperature compensation.
When readings are erratic or unstable, a small portion (1/8”) of the extendable cloth junction is pulled out to expose a fresh new surface.
Built-in Temperature Sensor
Error in calibration and measurement are eliminated with the Automatic Temperature Compensation provided by the integrated temperature sensor.
- Waterproof - The HI99151 is a waterproof meter rated IP67 for immersion in up to one meter of water for 30 minutes.
- Automatic Calibration - One or two-point calibration is automatic to two selectable buffer sets.
- Automatic Temperature Compensation – An integrated temperature sensor allows for automatic temperature compensation of pH measurements.
- Multi-Level LCD Display - The split-level LCD displays both pH and temperature readings, along with indicators for reading stability, battery percentage, and calibration instructions.
- On-Screen Tutorial - Clear tutorial messages and directions are available on-screen to quickly and easily guide users through setup and calibration.
- Battery Error Prevention System - The meter will automatically shut off if there isn’t enough power to obtain an accurate measurement.
- Battery Life Indicator - The battery percent level is displayed at start up alerting the user to the remaining battery power that is available.
pH Range -2.00 to 16.00 pH pH Resolution 0.01 pH pH Accuracy ±0.02 pH pH Calibration automatic, at one or two points with two sets of buffers (standard 4.01, 7.01,10.01 or NIST 4.01, 6.86, 9.18) Temperature Range -5.0 to 105.0°C / 23.0 to 221.0°F Temperature Resolution 0.1°C / 0.1°F Temperature Accuracy ±0.5°C (up to 60°C); ±1.0°C (outside) / ±1°F (up to 140°F); ±2.0°F (outside) Temperature Compensation automatic from -5.0 to 105.0ºC (23 to 221ºF) Electrode/Probe FC214D pre-amplified pH probe with internal temperature sensor, DIN connector and 1 m (3.3’) cable (included) Battery Type/Life 1.5V (3) AAA / approximately 1200 hours of continuous use; auto-off after 8 minutes of non-use Environment -5 to 50°C (23 to 122°F); RH max 100% Dimensions 152 x 58 x 30 mm (6.0 x 2.3 x 1.2”) Weight 205 g (7.2 oz.) Ordering Information HI99151 is supplied with FC214D pH/temperature probe, HI70004 pH 4.01 buffer solution sachet (20 mL), HI70007 pH 7.01 buffer solution sachet (20 mL), HI700661 electrode cleaning solution sachets (2 x 20 mL), batteries, instruction manual, and hard carrying case. Warranty 2 years (probe 6 months)