Using a microscope to help control yeast quality

For good brewing you need a healthy yeast with a good viability, a good cell count and free from contamination.

You can monitor the viability of your yeast by using a methylene blue stain, as dead or dying cells stain blue. The staining can be easily seen under a microscope. You can perform a yeast count by using a Haemocytometer. A haemocytometer consists of a defined grid etched onto the slide surface. The number of cells per ml can be calculated. There are two types of microbiological contamination, wild yeasts and bacteria, both these contaminants can cause hazes and off flavours. You can monitor the presence and levels of contamination using the microscope, by identifying rod shaped bacteria (bacilli) and round shaped bacteria (cocci). You can observe for wild yeast by looking at cell shape, size, opacity and uniformity. This often goes hand in hand with knowing your own yeast and getting to know its appearance under the microscope . If you are interested in purchasing a microscope from Murphy and Son Ltd here are the following options:

SP30 Microscope

• The SP30 has many features that are normally found on microscopes of much greater price
• The optical parts are made from achromatic corrected glass and are standard Royal Microscopical Society (RMS) size
• The monocular head rotates through 360° and has a wide field x10 good quality eyepiece
• The quadruple position rotating turret is equipped with x4, x10, x40 and x100 achromatic RMS objectives, which when used commonly need magnifications of x10 and x400
• The x40 and x100 objectives have a spring loaded front lens element that retracts the lens into the objective on contact with the slide. In addition the stage has a safety stop with a similar purpose
• The slide platform is full mechanical stage with drop down coaxial controls that makes fine movement of the stage in the required direction very easy
• The double vernier scale also allow position identification on the slide
• The SP30 base has inbuilt LED illumin

Microscope Kit

• The SP30 Microscope
• Pastuer Pippettes x5
• Haemocytometer/counting chamber including x2 coverslips
• Methylene Blue Stain
• sterilin bottles x2
• Instructions