The first essential step to producing a high quality is to measure the pH of juice and must. The measurement of pH occurs at each step of the process from pre-fermentation, fermentation, post-fermentation and at bottling.
A variety of factors and processes depend on pH including microbial stability, sulfur dioxide effectiveness, malolactic fermentation performance, protein stability, and sensory attributes.
A wines microbial and chemical stability is influenced by pH due to the influence it has on the various forms of sulfur dioxide that will be present. Sulfur dioxide is responsible for protecting wine against oxidation and microbial activity. The molecular form of sulfur dioxide is most effective against microbes and is predominate at lower pH values. As the winemaking process progresses pH levels can change due to acid conversion and other metabolic activity. These changes require frequent monitoring of the pH values and sulfur dioxide levels of wine being stored or aged.
Most wines have a pH value between 3.0 and 4.0. White wines tend to have pH values between pH 3.0 and 3.3, while higher pH values between 3.3 and 3.5 are more common for reds. Red wines sometimes have a higher pH, in part, due to the longer contact time the grape juice has with the grape skins. Early in the winemaking process and sometimes at points throughout, it may be necessary to make acid additions in order to set and maintain an optimum pH range for the desired style or condition of the wine. The pH of finished wine may also affect its color. For example, pigment compounds in the wine express different hues of color depending on the pH.
Below are the most common products measuring pH during the wine making process.
Benchtop pH meters include the HI5000 and edge tablet designed meters.
The HI5000 series is our most advanced benchtop pH meters incorporating the latest microprocessor to bring exceptional features and performance for the most demanding user. These meters are completely customizable to user specific requirements and include versions that can be used with ISEs for measurement of ammonia and potassium.
The edge meters are very unique in design and in the use of digital electrodes. The edge is designed in a tablet style that is a hybrid between the flexibility of being used as a portable or as a benchtop. The edge meter uses digital electrodes and the buffer set is automatically updated when using the wine must electrode to pH 3 instead of pH 4 to better bracket the wine sample expected reading. The edge multiparameter version can be upgraded with other probes to measure conductivity for tartrate stability or dissolved oxygen.
Application specific portable meters are available that are designed specifically for use with wine. The portable meters use the HI1048 wine must electrode that has a ground glass junction and a PTFE sleeve. This design resists clogging from solids that would degrade performance that can result inaccurate readings.
A variety of testers are available including general purpose and application specific meters. The application specific meters include a pH tester and the Halo® wireless Bluetooth® electrode that hav a ground glass junction and a PTFE sleeve. This design resists clogging from solids that would degrade performance that can result inaccurate readings. The Halo pH electrode is compatible with most smart devices turning them into a precion pH meter.
A variety of pH electrodes are available that include application specific versions made specifically for grape juice and must to traditional laboratory version.
Halo Bluetooth wireless pH electrodes that can be used with edge wireless or a compatible smart device can also be found in this category.
In this category are pH calibration buffers including pH 3.00 used with the grape juice/must pH electrode and pH 8.2 used in the titration of total titratable acidity and Yeast Assimible Nitrogen. The pH calibration buffers are available in a variety of sizes from single use sachets to bottles.
Maintenance solutions include both cleaning, storage, and probe refill solutions.
Cleaning solutions are available that are made specifically for cleaning wine stains and deposits from the pH sensitive glass can also be found in this category.
Accessories include magnetic stirrers, stir bars, and plastic beakers used when taking a pH measurement. Also available are shockproof rubber boots used with the portable meters. These boots give additional protection from accidental drops and provide for a more tactile feel when holding the meter.