1、BS5752-2:19840 IntroductionThe oven shall have a heating capacity such that盈The routine method for the determination of thehaving been set at a temperature of 130C,it is ableto regain this temperature in less than 45 minmoisture content of green coffee is based on the(preferably in less than 30 min)
2、after the insertionprinciple of the compensation of errors leading to aof the maximum number of test portions that can below result(moisture not completely removed,dried simultaneously.oxidation of products)and errors leading to a highresult(removal of substances other than water).5.2 Dish with lid,
3、of corrosion-resistant metal or ofglass,with an effective surface area of atIt is observed,indeed,that the loss in mass after theleast 18 cm2(for example 50 mm minimumfirst period in the oven is less than the moisturecontent determined by the basic reference methoddiameter and 25 to 30 mm deep)(ISO
4、1446)and that the total loss in mass after the5.3 Desiccator containing reagent-gradesecond period of drying is greater than this moisturephosphorus(V)oxide(P2O)or any other effectivecontent.The loss in mass after the first period in thedehydrating agent.oven may,therefore,be considered as an5.4 Ana
5、lytical balanceunderestimate of the moisture content.6 Procedure品The compensation between these two errors is madeby means of an empirical correction determined6.1 Test portionXexperimentally.Weigh the dried dish(5.2)with its lid,to the1 Scope and field of applicationnearest 0,002 g.Introduce approx
6、imately 5 g ofgreen coffee taken from the laboratory sample寸This International Standard specifies a routineobtained as specified in ISO 4072.Spread this test:4.kmethod for the determination of the moistureportion over the bottom of the dish in a single layercontent of green coffee.of beans.If the te
7、st portion contains a heavyimpurity(nail,stone,piece of wood,etc.),discard the2 Referencestest portion and take a new portion from the吉ISO 1446,Green coffee-Determination of moisturelaboratory sample.Cover the dish with its lid and品content(Basic reference method).weigh the dish plus lid plus test po
8、rtion to thenearest 0,002 g.(See 8.1.)ISO 4072,Green coffee in bags-Samplingl)6.2 Determination3 Definition6.2.1 First period in the ovenmoisture of green coffeePlace the lid of the dish in the oven(5.1),controlledconventionally,the loss in mass determined underat 130+2C,and place on the lid the dis
9、hthe operating conditions specified belowcontaining the test portion(6.1).Remove the dishafter a period of 6 h+15 min,cover it with the lidthe moisture content is expressed as a percentage byand place it in the desiccator(5.3).After cooling tomassambient temperature(from 30 to 40 min after4 Principl
10、eplacing it in the desiccator),weigh it,still closed,tothe nearest 0,002 g.After weighing,replace the dishDrying of a test portion at a temperaturein the desiccator for at least 15 h.of 130+2C,at atmospheric pressure,in two stages6.2.2 Second period in the ovenwith an intermediate rest period,in ord
11、er toredistribute uniformly the moisture in the beanUnder the same conditions as specified in 6.2.1.replace the dish in the oven at 130+2C and let it.R.The result thus obtained,after a correction has beenremain there for 4 h+15 min.Remove it,allow it toapplied,is regarded as agreeing with that provi
12、dedcool to ambient temperature in the desiccator andby the basic reference method(ISO 1446).weigh again.5 Apparatus6.3 Number of determinations5.1 Electrically heated constant-temperature ovenCarry out at least two determinations on the samehaving effective ventilation and capable of beingsample.regulated in such a way that the temperature of theair and of the shelves carrying the test portionsis 130+2C in the vicinity of the test portions)At present at the stage of draft.oBSI10-1999