New yeast strains isolated
New strains of wine yeast are continuously being isolated and adopted by commercial vineyards but, as with so much regarding winemaking, they remain a closely guarded secret. Vintner’s Harvest entered into an exclusive yeast strain screening program with a leading yeast and ingredient supplier to the European commercial winemaking industry. This program considered only specialist wine yeast strains used commercially in Europe and identified a complete wine yeast range for all varieties of Grape, Fruit and Vegetables. The screening process involved 3,000 separate fermentations over a two year period.
CL23 Saccharomyces Bayanus
Ideal for crisp, fresh dry white/blush and all sparkling wines. Also the best strain for high alcohol tolerance.
CL23 produces very low levels of fusel oils and other congener compounds during fermentation and so does not contribute much to wine flavour or aroma and can therefore be considered to be a particularly neutral / clean fermenter. However CL23 does contribute significantly to the wines structure and ferments out sugars completely allowing for the driest of wines to be made. CL23 is noted for its robus
tness, being able to ferment to 18% abv. ethanol, tolerate high free SO2 and high levels of other stress factors such as organic acids, incorrect temperature and pH making CL23 the strain of choice for high alcohol wines or where uncertain recipes are employed and fermentation reliability is a key factor or where low temperature fermentation down to 8OC (46 OF) is required. This strain is ‘fermentation friendly’ in that it produces zero foam, starts fermenting rapidly so avoids potential bacterial contamination and can be used to re-start stuck fermentations. In certain situations, CL23 can be used for red winemaking – especially where wine structure and dryness are key factors – but a word of caution, CL23 will take out colour and fruit flavour so recipes should be adjusted accordingly. To appreciate such attributes, split a Cabernet Sauvignon Must and ferment out using CL23 versus VR21 – you will not believe both wines came from the same grape.
MA33 Saccharomyces Cerevisiae
Acid reducing strain excellent for fruity white & blush country wines especially where residual sugars are desired. MA33 has the ability to metabolize between 30 and 35% of malic acid making this strain the perfect choice for country fruits which are naturally high in acid. Reducing malic acid will soften the wine and
give a vin nouveau character for early consumption with a balanced palate. MA33 is also noted for its production of fruity esters and fusel oils conferring fresh fruity character to the wine. There is an increased
chance of Malolactic fermentation by lactic acid bacteria following MA33 fermentation. MA33 is a killer-sensitive strain. It is a good fermenter between 18 and 27OC (64 -80OF), with a rapid onset to fermentation although can exhibit a slow late fermentation profile and may require aeration after 10 – 12 days fermentation. Will ferment up to 14% abv. ethanol providing the pH is above 3.2.
AW4 Saccharomyces Cerevisiae
The ‘only strain’ for Germanic aromatic white wines. AW4 is noted for developing powerfully fragrant, full spice aromatic wines and is a perfect match for Gewurztraminer and also recommended for Sauvignon and Semillon where the Oenologist requires a positive aromatic esters contribution from the yeast. AW4 is a good fermenter across the range 14 to 30OC (57 -86OF), low foam formation and medium to high glycerol. It will ferment up to 14.5% abv. ethanol providing the temperature is held within the 20 - 25OC (68 -77OF) range and the pH is above 3.0.
CY17 Saccharomyces Cerevisiae
Perfect for sweet white/blush and dessert wines from grape and particularly from country fruits & flowers.
CY17 produces high levels of desirable congeners during fermentation including aromatic thiols, imparting rich fruity aromatics, full body and ‘tropical’ flavour characteristics to the wine. CY17 is also noted for high glycerol formation further enhancing sweetness. This is a slow fermenter compared to all other strains in the Vintner’s Harvest range typically taking up to 21 days to ferment table wines and up to 35 days for dessert wines. CY17 prefers a constant temperature in the 22 – 26OC (72 -78OF) range. Dropping the temperature below 15OC (59 OF) two-thirds the way through fermentation will arrest fermentation making CY17 suitable for producing naturally sweet wines (both potassium sorbate and metabisulphite must be used to prevent re-fermentation). CY17 is also excellent for sweet sparking wines, but strain CL23 must be employed for the bottle fermentation stage. Avoid free SO2 levels above 50 ppm and ensure pH above 3.2, CY17 is a delicate strain that must be treated with some respect. Pay particular attention to sterile winemaking conditions and a warm start to fermentation otherwise risk of bacterial contamination is increased. CY17 will happily ferment up to 15% abv. ethanol if such conditions are employed.
BV7 Saccharomyces Cerevisiae
Ideal for full bodied, full flavoured dry and sweet white wines. BV7 will both preserve and enhance the grape variety and terroir, promoting excellent flavour complexity, good wine structure and balance but especially FULL AROMATIC FLAVOUR. To appreciate the impact of BV7, split a chardonnay must, fermenting half with CL23 and the remainder with BV7 – you will be amazed at the impact of the yeast strain upon fruit concentration. BV7 produces a wide range of low level beneficial congeners such as higher alcohols and esters and high glycerol promoting full body and structure to the wine and contributing significantly to mouth-feel, wine texture and palate intensity. Avoid fermenting above 13% abv. ethanol, BV7 is not particularly ethanol tolerant. Acceptable temperature range is 15 to 30OC (59 -86OF) but ferment below 22OC (72 OF) for maximum flavour development.
