Page 12 - Grapevine JanFeb 2022

In The Winery

oxide (H2O2) reacts with the SO2 to form H2SO4 • 100 milliliter graduated cylinder
(a very low concentration sulfuric acid) and H2O • Burette stand and a burette clamp
(water). This in turn lowers the ph of the Hydrogen • Vacuum source (adjustable) – only a light vacu-
Peroxide collection flask and then the lab techni- um source is needed.
cian can titrate this sample with a weak base. The • Aeration oxidation apparatus
weak base is measured volumetrically to determine • Distilled water
how much of the base it took to neutralize the acid
sample and then mathematically use that to formu- Mixing and Standardizing Chemicals
late the Sulfur Dioxide content of the wine being
tested. • Purchase or pre-mix your sodium hydroxide to
0.01 Normal.
Tools and Chemicals
• Standardize the 0.01 Normal Sodium Hydroxide
• 25% Phosphoric acid against the 0.01 Normal Potassium Acid
• 30% Hydrogen Peroxide Phthalate or 0.01 HCL. Do this daily before
• 0.01 Normal Sodium Hydroxide each day’s work with this unit to be certain your
• 0.01 Normal Potassium Acid Phthalate or results will be accurate. This is a critical part of
Hydrochloric acid. this test because it must be exact!
• Aeration oxidation indicator dye
• 10 milliliter burette – class A volumetric • Purchase or premix the 25% Phosphoric acid.
• 20 milliliter pipette - class A volumetric Pre-mixing may be done by adding 1 portion of
• 25 milliliter delivery cup squeeze bottle set at 10 85% phosphoric acid to 2 portions of distilled
milliliters delivery - approximate. water. Example: 333.33 milliliters phosphoric

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