Sulfur Dioxide Mini Titrator for Wine

The HI84500 can be used to test for free and total sulfur dioxide in all wines, including red, which are difficult to test using traditional methods due to the inability to see the distinctive color change that occurs at the endpoint. The HI84500 offers reliable, accurate, and fast wine analysis. This mini titrator dispenses the titrant, detects the endpoint, and performs all necessary calculations automatically in a fraction of the time as compared to a manual titration. As found in Triage for Basic Wine/Grape Lab by Richard Carey, "the mini-titrator by Hanna reduces the time for an individual analysis by 75%.in.

Winemakers add sulfur dioxide (SO₂) to wine in order to inhibit bacteria and wild yeast growth and to serve as an antioxidant to prevent browning. When SO₂ is added to wine, a portion of it becomes immediately bound while a remaining portion is unbound SO_2. The portion that is unbound is also called free SO₂ and it is responsible for protecting the wine. The bound and free SO₂ together are referred to as total SO2. The relationship between the amount of SO2 added and the amount of free SO₂ is complex, governed by the total amount of SO₂ in the wine and the ability of compounds (e.g. sugars, aldehydes, keto acids, quinones, anthocyanin) to bind to the SO₂. The exact relationship between free and bound SO₂ will vary from wine to wine.

The amount of free SO₂ depends on how much is added, how much was present before the addition, and how much was immediately bound. Free SO₂ exists in two forms. The first form, bisulfite (HSO₃^-), is the predominant form but is relatively ineffective. The second form, molecular SO₂, is the minor form and is responsible for protecting the wine. The amount of molecular SO₂ available in wine is dependent upon the amount of free SO₂ present and the pH. Typically 0.8 ppm of molecular SO₂ provides adequate protection against bacteria growth and oxidation. In order to obtain this value for a wine sample that has a pH of 3.2 you would need 22 ppm of free SO₂. If the pH was at 3.5 you would need double the amount of free SO₂, 44 ppm.

Application-Specific ORP Electrode

The HI84500 is supplied with the HI3148B ORP electrode featuring CPS™ technology to prevent the clogging of the reference junction. Conventional electrodes may clog quickly in samples such as wine that have a high suspended solids content. By design, the HI3148B ORP electrode utilizes a ground glass/PTFE sleeve junction that controls a steady, predictable flow of electrolyte solution, keeping the junction open. The hydrophobic properties of PTFE repel wetness and coatings.

Piston Driven Dosing Pump

The heart of the HI84500 is the piston driven burette pump. This type of dosing system uses a motor in which each dose is very precisely controlled and the volume dispensed is accurately determined. The piston driven burette is controlled dynamically so that the volume of titrant being dosed is automatically adjusted based on a voltage response of the previous dose. This type of dosing speeds up the titration process by allowing for more titrant to be dosed at the start of the titration and then very small doses as the endpoint is reached.

Automatic Stirrer

The built-in stirrer is automatically maintained at a speed of 700 rpm, regardless of the viscosity of the solution being titrated.