Frequently Asked Questions
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FAQ - Color Analysis
The ETS Color Analysis
  1. What is the difference between the 420:520 ratio measurement of hue and CIE hue angle?
    The 420:520 hue ratio is based on two wavelengths: the 420 nm for indicating yellow and the 520 nm for red. In contrast, the CIE hue angle is based on the entire wine spectra. Hue angle is more descriptive of color nuance and, as a result, is more sensitive to subtle changes in wine chemistry and a more accurate representation of color present. What's more, the CIE hue angle can describe any color. The 420:520 ratio is only appropriate for red wines.

  2. Can you compare the same wine at two different dates?
    Yes, wine color information can be databased at ETS and retrieved for comparison against itself at different points in its life cycle. The key lies in the goal and the timing of the initial sample. For color development at the winery, a good time to sample is when the wines are going to barrel. For tracking changes in color after shipment, samples should be taken at bottling.

  3. Can you analyze turbid or cloudy wines?
    Since turbidity scatters light and can interfere with accurate measurement, turbid samples- such as fermenting wines- should be centrifuged prior to analysis to remove particulates. Some very turbid samples- juices, for instance- may also require filtration. Turbidity issues and any resulting treatments are always flagged and detailed in the comments section of the report.

  4. Does this report work for white wines?
    Yes, the report is extremely valuable for white wines. The CIE coordinates, hue angle and chroma data contained within the report very accurately describe white wine colors, making up for the fact that 520 nm information has little, if any, relevance to white wines.

  5. Doesn't color depend a great deal on the ambient light?
    Absolutely. Light quality has a profound effect on visual impressions. The CIELab measurements describe color under one several precisely defined light sources. For the Wine Color Report, ETS uses CIE D650, which describes the color of objects as they might appear outside under a cloudy sky.
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