Decagon Devices AquaLab 4TE Operator's Manual page 13

AquaLab
2. About AquaLab
Th ere are several advantages in having a temperature-controlled wa-
ter activity meter. A few major reasons are:
1. Research purposes. Temperature control can be used to study
the eff ects of temperature on the water activity of a sample, make a
comparison of the water activity of diff erent samples independent
of temperature, and conduct accelerated shelf-life studies or other
water activity studies where temperature control is critical. Th ere are
many shelf-life, packaging, and isotherm studies in which tempera-
ture control would be very benefi cial.
2. To comply with government or internal regulations for specifi c
products. Th ough the water activity of most products varies by less
than ± 0.002 per °C, some regulations require measurement at a spe-
cifi c temperature. Th e most common specifi cation is 25°C, though
20°C is sometimes indicated.
3. To minimize extreme ambient temperature fl uctuations. If the
environmental and AquaLab temperatures fl uctuate by as much as ±
5°C daily, water activity readings will vary by ± 0.01 a . Temperature
w
control eliminates variations due to changes in ambient conditions.
Series 4TE/4TEV/4TE-DUO
Th e AquaLab Series 4TE models have thermoelectric components
installed to allow the instrument to maintain a set chamber tem-
perature. Th e temperature is set using the confi guration menu of any
of the Series 4 models.
7