Yeast assimilable nitrogen

Slow and stuck fermentations are often associated with sulfide formation. This new analysis is available to provide wineries with information about the nitrogen status of their juice and to avoid or minimise nitrogen related fermentation problems. The analysis will also provide information that will allow wineries to determine optimum additions of di-ammonium phosphate (DAP).

YAN is measured in two steps using the Randox Daytona enzymatic analyser, as total nitrogen cannot be quantified by measuring only ammonia. The first step involves measurement of alpha amino nitrogen. It does not detect secondary acids such as hydroxy proline or proline (which is not utilised by yeast), nor does it detect ammonia. The second step determines the amount of ammonia present. The two measurements together enable YAN to be calculated.

Samples must be submitted for this analysis in plastic containers and frozen prior to despatch. Samples that have commenced fermentation will not give accurate results.

For further information on yeast assimilable nitrogen, please refer to Institute publication # 587 (Weeks and Henschke 1999).

Prices per analysis
Analysis Per Sample (excluding GST) Volume required Target response time
YAN (Yeast assimilable nitrogen including alpha amino nitrogen and ammonia) $35 10 mL 24 hrs after receipt of samples

Other relevant price combinations see Grape and colour analysis for more information:

Prices per analysis
Analysis Per Sample (excluding GST) Volume required Target response time
Basic Vintage Panel (Brix or Baumé / pH/ Titratable acidity) $24 200 berries or 50 mL 24 hrs after receipt of samples
White/Red Grape Vintage Panel (Brix or Baumé / pH/ Titratable acidity /YAN) $55

For more information, please contact AWRI Commercial Services on (08) 8313 6600 or e-mail commercialservices@awri.com.au