Examination by microscopy

Once isolated, the material comprising the haze or deposit may be examined by microscopy. Larger particles may be examined by stereomicroscopy, while phase-contrast microscopy is suitable for finer particles. The material is usually resuspended in a small drop of wine and transferred to a clean microscope slide. A coverslip is placed on the specimen and gently pressed into place, with the tip of a pencil, for example. A tissue may be placed at the edge of the coverslip and used to draw excess liquid from underneath.

The objective lens that gives the most appropriate magnification should be used, and the correct phase ring for that objective then selected. Immersion oil is required when using the 100x objective; the objective should be swung out of the light path by rotating the nose-piece which holds the various objectives, a drop should be placed on the cover slip in the vicinity of the light beam, and the 100x objective then swung back into the light path. Note that immersion oil should never be allowed to contact any of the other objectives, and should always be removed immediately after use, by gently yet thoroughly wiping with a lens tissue moistened with ethanol.

An ocular micrometer may be used to estimate the size of an object; the actual size of the object can be calculated by multiplying the apparent size in terms of graduations by the ocular micrometer factor.

Experience has shown that the 40x objective is generally suitable for most hazes and deposits, at least initially.