What fill accuracy should I specify for 250 g and 1 kg coffee bags?

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Specify plus or minus 1 g net weight on a 250 g bag, and plus or minus 2 g on a 1 kg bag. As a share of fill that is 0.4% and 0.2%. Anything looser than plus or minus 2% on a 250 g bag is not a coffee specification, it is a rounding error with a retail price attached.Our linear weighers hold 0.1 to 1.5 g on whole beans. The number you write in the enquiry decides whether you get that or a volumetric cup.Accuracy as a share of fill, not as a gram figureBag fillSuggested toleranceAs % of fillWhat one extra gram costs per year250 g±1 g0.4%500 kg at 500,000 bags a year500 g±1.5 g0.3%500 kg at 500,000 bags a year1 kg±2 g0.2%500 kg at 500,000 bags a yearAt US$8 per kg green-equivalent cost, one gram of give-away per bag on half a million bags is about US$4,000 a year. Two grams is US$8,000. That is usually more than the difference between a volumetric filler and a load-cell weigher.A 250 g fill is where tolerance matters most: the bag and valve are 5 to 8 g of the gross weight.Sealing jaws close on a settled product column. If the weigher has not settled, the seal carries the error into the bag.Recipes store fill weight and seal parameters together. That is why the tolerance should be written into the recipe, not left to the operator.Three things in the specification that decide the resultSay “net weight”, not “weight”Gross weight includes the bag and the valve. On a 250 g retail bag that is 5 to 8 g of packaging hiding inside your tolerance.Name the product formWhole beans flow; ground coffee bridges and holds air. The same weigher behaves differently on each, so the tolerance has to be quoted per product.State the sampling basisTen consecutive bags, or a two-hour production average? The second number always looks better and is far less useful at the retail checkweigher.Ask for the test reportA material test on your own beans and your own film is the only figure worth trusting. We run one before an order is placed.Why a volumetric cup cannot hold thisA volumetric cup measures volume, and ground coffee density swings with roast level, grind setting and humidity. A cup set at 250 g on Monday can deliver 245 g on Friday after a roast change, and nothing on the machine tells you. A load-cell weigher measures mass directly, which is why the tolerance is stable across a roast profile.The limitation to state up front: plus or minus 1 g at 30 bags a minute requires the weigher to settle between cycles. Above roughly 40 bags a minute on a small bag, holding 1 g usually needs a different weigher configuration rather than a faster machine. Decide which of the two you need before the quotation stage.The bean-line weigher that holds 0.1 to 1.5 g is specified on our coffee bean packing machine page. For how beans and ground coffee differ mechanically, see ground coffee versus whole bean packaging.Compare coffee packaging machines

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What fill accuracy should I specify for 250 g and 1 kg coffee bags?

Accuracy as a share of fill, not as a gram figure

Three things in the specification that decide the result

Why a volumetric cup cannot hold this

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Bag fill	Suggested tolerance	As % of fill	What one extra gram costs per year
250 g	±1 g	0.4%	500 kg at 500,000 bags a year
500 g	±1.5 g	0.3%	500 kg at 500,000 bags a year
1 kg	±2 g	0.2%	500 kg at 500,000 bags a year