Measuring Yeast Assimilable Nitrogen (YAN)
Maintaining an adequate supply of nitrogen is essential for a successful fermentation, as both deficiency and excess of nitrogen can cause problems.
Increased production of hydrogen sulphide is associated with low nitrogen availability, which can then lead to sluggish or stuck ferments.
Conversely, excess nitrogen present at the completion of fermentation can be used by undesirable microorganisms, which can lead to wine spoilage.
Managing nitrogen levels is necessary to avoid these problems and to maximise the control you have over the fermentation.
This is initially achieved through vineyard practices such as the application of nitrogen-containing fertilisers. However, many factors can affect the level of nitrogen in the must just prior to fermentation.
These factors include grape variety and rootstock, soil type, geographic location, seasonal variation and juice clarification practices.
So while careful vineyard practices are a good starting point, measuring YAN is the only way to accurately determine the amount of available nitrogen in juice prior to fermentation. Nitrogen levels can then be adjusted before fermentation starts with the addition of DAP or other nutrients.
Vintessential can analyse your samples for YAN quickly and accurately, or we can supply the YAN test kit package for you to do it yourself.
Further information on YAN measuring options and prices.