pH is an essential measurement throughout the entire cheesemaking process. From the initial measurements of incoming milk to the final measurements of ripened cheese, pH is the most important parameter for cheese quality and safety control.
Acidification of milk begins with the addition of bacterial culture and rennet. The bacteria consume lactose and create lactic acid as a byproduct of fermentation. The lactic acid produced will cause the pH of the milk to go down. Once the milk reaches a particular pH, the rennet is added. The enzymes in rennet help to speed up curdling and create a firmer substance. For cheesemakers that dilute their rennet, the pH of the dilution water is also critical; water that is near pH 7 or higher can deactivate the rennet, causing problems with coagulation.
Once the curds are cut, stirred, and cooked, the liquid whey must be drained. The pH of whey at draining directly affects the composition and texture of the final cheese product. Whey that has a relatively high pH contributes to higher levels of calcium and phosphate and results in a stronger curd. Typical pH levels at draining can vary depending on the type of cheese; for example, Swiss cheese is drained between pH 6.3 and 6.5 while Cheddar cheese is drained between pH 6.0 and 6.2.
During brining, the cheese soaks up salt from the brine solution and loses excess moisture. The pH of the brine solution should be close to the pH of the cheese, ensuring equilibrium of ions like calcium and hydrogen. If there is an imbalance during brining, the final product can have rind defects, discoloration, a weakened texture, and a shorter shelf life.
Cheeses must fall within a narrow pH range to provide an optimal environment for microbial and enzymatic processes that occur during ripening. Bacterial cultures used in ripening are responsible for familiar characteristics such as the holes in Swiss cheese, the white mold on Brie rinds, and the aroma of Limburger cheese. A deviation from the ideal pH is not only detrimental to the ecology of the bacteria, but also to the cheese structure. Higher pH levels can result in cheeses that are more elastic while lower pH levels can cause brittleness.
Cheese products can provide a number of challenges for the person that needs to measure pH. Cheese products tend to be solid to semi-solids. Both types of samples will coat the sensitive glass membrane surface and/or clog the reference junction. The FC2423 that is supplied with the HI98165 is designed specifically for measuring pH in cheese. From a conic tip shape in a durable 5 mm diameter stainless steel body for easy penetration into cheese without leaving a large hole to an open junction that resist clogging; the FC2423 is an ideal general-purpose pH electrode for cheese. The FC2423 connects to the HI98165 with a quick-connect, waterproof DIN connector, allowing for a secure, non-threaded attachment.
Features
- Ergonomic, rugged, waterproof (IP67) design
- Supplied with FC2423 Foodcare pH/Temperature electrode
- Durable stainless steel body that is only 5 mm in diameter
- Conic tip shape for easy penetration into semi-solids
- Open junction design that resist clogging from food solids
- Built in temperature sensor for temperature compensated measurements
- Five-point pH calibration with seven standard buffers and five custom buffers
- CAL Check
- Alerts user to potential problems during calibration including when to clean electrode and possible buffer contamination
- Displays overall condition of the pH electrode after calibration that is based on the offset and slope characteristics
- Log-on-demand
- Store measurement data at the press of a button
- AutoHold
- Freezes displayed measurement reading upon stabilization
- GLP Features
- GLP data including date, time, pH calibration buffers, offset, and slope
- GLP data stored with logged data for traceability
- Calibration timeout to alert the user at a defined interval when the calibration has expired
- Multiple language selection
- 200 hour battery life with battery level displayed on measurement screen
- Menu driven for ease of use with virtual-key extended functionality
- Contextual help at the press of a button
- Backlit, graphic LCD
- Connectivity
- PC connectivity via a sealed opto-isolated micro USB and HI92000 software
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