Vinmetrica YAN test kit
The value of the test is that it can be completed as a sequentially step following pH and TA measurement of must or juice using a common pH pen and 0.133M NaOH solution for TA titration. No special equipment is required other than the pH pen but it does require attention to detail by the person performing the test. For more information refer to our club website in regards to the NaOH solution Preparation of Standard Sodium Hydroxide Titration Solutions for Winemaking
To supplement info on the Youtube video below note that the sample size of grape juice is 10 ml diluted with 10 ml water. End point of titration for TA determination is pH 8.2 using O.133 M Na OH. TA = ml of TA titrant used .
When the end point has been reached add 1 ml of YAN reagent that you have adjusted using the above mentioned NaOH solution to pH 8.0. Addition of the reagent drops the pH in the sample. Titrate back to pH 8.2 with NAOH solution. The formula for converting volume of titrant to YAN is: ml titrant x 0.133 x1400 = mg/L yeast assimilable nitrogen. Instructions on formalin disposal included with the test.
Youtube instructions: 10:48Measuring Yeast Assimilable Nitrogen (YAN)