Tuesday, December 22, 2015

Wednesday, December 16, 2015

Beer Brewing & Wine Making Microscopes

Whether you are an expert home brewer, own a company brewing beer, or own a vineyard, a quality beer brewing or wine making microscope can make your job much easier. Here are a few things to look for when selecting a microscope.

Beer Brewing Microscope Tips:

  • You will need magnification in the 400x to 1000x range in order to view cells, bacteria and yeast. If you simply want to count cells, a basic binocular compound microscope such as the basic beer and wine microscope with 400x magnification can do the trick.
  • Make sure you have coarse and fine focusing! The fine focus adjustment is important, especially when using the microscope at the higher magnifications.
  • Get a microscope with a mechanical stage. The mechanical stage will allow you to maneuver your slide in small increments and without frustration.
  • A monocular (single eyepiece) microscope will suffice, although if you spend much time looking through the microscope binocular (two eyepieces) will be much more comfortable.
  • Don't use a microscope with a disc diaphragm - an iris diaphragm on the condenser will allow you to enhance the contrast in your image when you close down the diaphragm.
  • Phase contrast is the best technique for looking at both yeast and bacteria. Phase contrast microscopes vary from simple phase contrast (usually only 40x phase objective) to full phase contrast which provides phase contrast 4x, 10x, 40x, 100x objectives. Phase contrast will allow you to view enhanced images of both yeast and bacteria.
  • Cell counting can be performed with a grid eyepiece reticle or with measurement software included with the microscope digital camera. A hemocytometer is used for counting.
  • The Brewing Science Institute has some great educational info here.
When viewing yeast through the microscope you will use the 40x lens (400x total magnification). Notice whether the cells are bacilli (rod shaped) or cocci (round shaped). Phase contrast will allow you to view yeast or bacteria that is often the same color as the background it is against.

Beer and wine microscopes vary from basic phase contrast and digital basic phase contrast to more advanced full phase contrast microscopes or even an advanced fluorescence beer/wine microscope in order to perform live-dead tests.

Winery and beer brewery microscopes for identifying bacteria, yeast, and mold.
Beer Brewing / Wine Making Microscope

Wine Microscope Tips:

Here are a few tasks every vintner should be able to perform with a microscope.
  • Distinguish between bacteria, yeast and fungi under the microscope. 
  • Identify and differentiate living organisms from plant debris, filter agents or crystals.
  • Identify the most common organisms by sight in order to take action quickly if needed - including wine yeast, mold and bacteria. Phase contrast microscopes are helpful when viewing bacteria and yeast.
  • Count yeast cells and distinguish between living and dead cells.
The easiest way to differentiate bacteria, yeast and mold is by size. Molds are easy to view at 100x magnification, yeast at 400x, and bacteria at 400x or 1000x. Determining if cells are living or dead is best performed by looking at symmetry. Debris tends to be asymmetric, while living organisms are symmetric. View more wine making microscope tips here.

Tuesday, December 8, 2015

Wright's Stain for Microscopy

Wright's stain is a histologic stain that facilitates the differentiation of blood cell types. It is classically a mixture of eosin (red) and methylene blue dyes. It is used primarily to stain peripheral blood smears and bone marrow aspirates which are examined under a light microscope. In cytogenetics, it is used to stain chromosomes to facilitate diagnosis of syndromes and diseases.

Wright's stain is named for James Homer Wright, who devised the stain in 1902. The stain is actually a modification of the Romanowsky stain. Because Wright's stain distinguishes easily between blood cells, it became widely used for performing differential white blood cell counts, which are routinely ordered when infections are suspected.

The blood smear images below have Wright's stain applied to them and were captured with a laboratory microscope.

Blood smear with wright's stain under the microscope at 40x magnification.
Blood smear with Wright's Stain captured at 40x under a clinical lab microscope.

Blood smear with wright's stain under the microscope at 100x.
Blood smear with Wright's Stain captured at 100x under a clinical lab microscope.

Microscopy image of blood cells at 400x magnification.
Blood smear with Wright's Stain captured at 400x under a clinical lab microscope.

Blood smear with Wright's Stain captured at 400x under a clinical lab microscope using a Plan Fluor objective.

Friday, December 4, 2015

Understanding Microscope Resolution

A common misconception among first-time microscope purchasers is that more magnification is always better. Unfortunately, any microscope that advertises magnification above 1000x is offering empty magnification. You can learn more about empty magnification here. The limiting factor in a microscope is not its magnification, but rather its resolution. Resolution refers to the shortest distance between two separate points in a microscope's field of view that can still be distinguished as distinct entities.

Imagine a drawing that was made with large children's crayons, versus a drawing made with a sharp pencil. Microscopes with poor resolution will provide images that are similar to the crayon drawing, as the images will not be crisp and clear.

Numerical aperture determines the resolving power of a microscope objective lens, but the total resolution of the entire microscope is also dependent on the numerical aperture of the condenser (located beneath the stage on a compound biological microscope). The higher the numerical aperture of the complete microscope system, the better the resolution will be.

Aligning the microscope optical system is also important to ensure maximum microscopy resolution. The condenser must match the objective with respect to numerical aperture and adjustment of the aperture iris diaphragm. There is a great article here that discusses how to properly align the condenser as well as set the field iris diaphragm. The sketch below shows alignment of the iris diaphragm on the condenser (3) to match the objective value (4) of the current objective being used.

Lining up the iris diaphragm on the microscope condenser.
Iris Diaphragm on Microscope Condenser
Wavelength of light is an important factor in the resolution of a microscope. Shorter wavelengths will yield higher resolution. Therefore, the greatest resolving power in optical microscopy is realized with near-ultraviolet light which has the shortest effective imaging wavelength. When using near-ultraviolet light special Near-Ultraviolet microscope objectives are used.

The resolution of a microscope provides the ability to view samples and specimens clearly. The main factor in determining resolution is the objective numerical aperture, but resolution is also dependent upon the type of specimen, coherence of illumination, degree of aberration correction and other factors such as contrast enhancing methodology in either the microscope's optical system or the sample itself.

Contributing Source: MicroscopyU