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GENERAL DESCRIPTION
SIGNIFICANCE OF USE
The nitrogenous compounds of must and wine are deriving from grapes and play important role in
fermentation, clarification, and potential microbial instability of wines. They are profoundly modified
during the alcoholic fermentation by the physiologic activity of yeast. Thus, yeast assimilates
60-70% of the must nitrogen, ammonium ion completely disappearing during the fermentation
and the total nitrogen being slightly reduced.
Ammonia is present in grapes as ammonium ion in a few milligrams amount and it serves as the
primary form of available nitrogen for yeast metabolism. So, the content of ammonium ion can
drastically decrease during the alcoholic fermentation, increasing again, especially in red wines, at the
end of the malolactic fermentation because the lactic bacteria release ammonia nitrogen in wine.
The amount of ammonium ion in must influences the rapidity of fermentation start and evolution.
The ammonia concentration ranges from 24 to 209 mg/L (ppm) in grapes and from a few mg/L
(ppm) to about 50 mg/L (ppm) in wine.
The
HI 84185
ISE Ammonia Nitrogen meter measures the ammonia nitrogen (N-NH
3
) content in
wine using an ion selective electrode. The used method is double standard addition, a simple and
rapid method of analysis, and the result is readily displayed in ammonia nitrogen (N-NH
3
) mg/L
(ppm).
The
HI 84185
is a low cost, easy to use, ammonia nitrogen (N-NH
3
) ISE instrument that performs
automatic analysis with all the necessary calculations assuring to the user a simple and effective
interface.
The instrument comes with a powerful and effective built-in algorithm to analyse the shape of the ISE
electrode response and to determine the reaction completion.
By simply pressing the
Start
key, the instrument performs automatic analysis, all the necessary
calculations and verifications. The result is immediately displayed in convenient units, then the
instrument is ready for another measurement.