MiniFerment™
Trial fermentations for brewers

BACKGROUND: 

Tests on our yeast: White Labs Inc. has tested its strains using micro-fermentation techniques over the course of many months using its proprietary MiniFerment process. The tests, which have been extensively refined over time, provide data that closely mirrors the final properties of large-scale beer. Notes on wort: White Labs used the same light colored wort to test each yeast strain. It is 12° Plato wort with IBUs of 37.5 and pH of 5.5 (both IBUs and pH are before fermentation). Fermentation temperature - Ales - 68°F , Lager strains: 55°F. Please note that these tests do not necessarily reflect the values you would get on your own beers (for more on testing your beers, read below), given different recipes and brewing conditions. However, they do provide hints as to how the strains behave on the exact same wort and under the same exact conditions of the MiniFerment.

Tests on your beers: The MiniFerment process is available to customers. White Labs utilizes as little as 2 liters of your wort to replicate large-scale batches. These tests provide reliable data about your beers, such as optimal aeration levels, fermentation temperatures, pH levels, and pitching rates. It is also an ideal way to test multiple yeast strains on the same wort. To get a quote visit here.

As for the White Labs strains, we will regularly update our yeast descriptions with information culled from the MiniFerments. The updates are also noted below on this page.

Data comparing different strains will also occasionally be updated on this site and will be noted below.

UNDERSTANDING THE DATA:

To understand the data included on individual yeast strain pages, or to understand the data supplied with a typical MiniFerment, we provide the following data about the compounds. These flavor compounds are divided into esters, fusel alcohols, and others. As for esters and fusels, even though there are many more compounds produced by yeast, these compounds are the ones traditionally tested to evaluate ester levels and fusel alcohol levels for beer. 

Flavor compounds:

Esters:

Ethyl Acetate: Fruity with solvent undertones when above the flavor threshold. Considered an off flavor in beer when in high concentrations. 

Isoamyl Acetate: Can produce banana and pear-like flavors when above the flavor threshold. 

Fusel Alcohols:

n-Propanol: Because the typical level in beer is below the flavor threshold (see below), this compound generally does not affect flavor. 

Isoamyl Alcohol: Can produce wine-like or solvent-like flavors when over the flavor threshold. 

Others:

Diacetyl: Butter like aroma at moderate to high levels. 

2,3-Pentanedione: Produces honey like aroma at higher levels.

Acetaldehyde: Grassy odors, bruised apples, cidery notes. Immediate precursor to ethanol. 

Flavor thresholds:

Notes on the above chart:

Some of your results (as well as the information about our own yeast strains) are reported in ppm; this is the same as mg/L as reported in the chart above. As for results reported in ppb, note that 1000ppb is equal to 1ppm (or 1 mg/L).

Attenuation

Apparent attenuation percentage is the percentage of sugars that yeast consume.  Attenuation varies between different strains. The fermentation conditions and gravity of a particular beer will cause the attenuation to vary, hence each strain of brewers yeast has a characteristic attenuation range. The range for brewers yeast is typically between 65-85%. 

UPDATES:

Yeast strains descriptions with MiniFerment data (the latest updates are first):  WLP800, WLP802, WLP810, WLP820, WLP830, WLP833, WLP838, WLP008,  WLP041, WLP072, WLP351, WLP500, WLP540, WLP051, WLP029, WLP023, WLP028, WLP002, WLP004, WLP001, WLP013, WLP011, WLP099, WLP300, WLP320, WLP380, WLP400, WLP530, WLP007, WLP550, WLP565, WLP570, WLP575, WLP740 Updated July 29, 2009.

Also, view the test results of fermentations trials using three different strains in the same wort. Updated July 8, 2008