Every batch record ends with a number that quietly decides whether the batch is closed cleanly or investigated: percentage yield. But by the time that final number shows up, the batch has already passed through four or five distinct stages, and each one has its own way of losing material. Treating "yield" as a single checkpoint at the end misses most of the useful information — the real value is in reconciling material stage by stage, so you know exactly where it went, not just that it went.
This is the logic behind stage-wise batch reconciliation, and it's worth understanding each stage on its own terms, because the causes of loss — and the fixes — are completely different from one stage to the next.
Granulation: the first checkpoint
Granulation is usually where a batch first commits to its final physical form, and it's also one of the more variable steps in solid dosage manufacturing. Losses here typically come from three places: fines carried out through the dust collection system, material adhering to mixer or granulator surfaces, and spillage during transfer to the dryer.
The reconciliation itself is simple — compare the theoretical powder or granule weight from the batch formula against what's actually recovered after drying:
% Loss = ((Theoretical weight − Actual weight) ÷ Theoretical weight) × 100The reason this stage matters more than it might seem is compounding. A 3% loss at granulation isn't just a 3% loss — it's a 3% shortfall that every later stage inherits and can only add to, never recover from. Catching an unusually large loss here, while the batch is still early, is far cheaper than discovering the same shortfall after tablets have already been compressed or coated.
One common mistake worth flagging: recording the actual weight before drying is fully complete. Residual moisture inflates the actual figure and makes the loss look smaller than it really is — the reconciliation should always be done on dried, in-spec material.
Compression: where losses become countable
Compression reconciliation compares the granules or powder fed into the tablet press against the tablets actually compressed — but rather than comparing weight to weight, the more useful check converts both sides into tablet counts, using the core tablet weight as the conversion factor:
Theoretical tablets = (Granules/powder weight × 1,000,000) ÷ Core tablet weight
Actual tablets = (Compressed tablets weight × 1,000,000) ÷ Core tablet weightThis stage often reveals losses that granulation reconciliation alone wouldn't catch: die-fill variation, tablets rejected during in-process weight checks, and material left behind in the feed frame or hopper at the end of a run. Reporting loss in both weight and tablet count is worth doing deliberately — weight loss is easier to compare across batches of different sizes, while tablet-count loss maps directly onto how many saleable units the batch actually produced, which is usually the number people actually care about when a batch record is being reviewed.
Coating: why weight alone lies to you
This is the stage where a naive reconciliation approach actively misleads. Coating adds weight to every tablet — so a coated batch will always weigh more than the core batch it came from, even if tablets were lost along the way. A direct kilogram-to-kilogram comparison would show an apparent "gain," which masks any real tablet loss underneath it.
The fix is to reconcile on a tablet-count basis instead, deriving the expected coated batch weight from the theoretical tablet count and the actual average coated tablet weight:
Theoretical tablets (core) = (Core tablets weight × 1,000,000) ÷ Core tablet weight
Actual tablets (coated) = (Coated tablets weight × 1,000,000) ÷ Avg. coated tablet weightLosses at this stage typically come from pan wall buildup, fines and chipped fragments carried out with the exhaust air, and tablets rejected during a post-coating appearance check. Because the numbers involved are less intuitive than a simple weight comparison, this is the stage where I most often see reconciliation done incorrectly in practice — usually by comparing core and coated weights directly and drawing the wrong conclusion from it.
Encapsulation: the shell complicates things
Encapsulation reconciliation has a similar wrinkle to coating, but from the opposite direction: a filled capsule's weight includes both the fill material and the empty shell, so comparing fill material weight directly against total filled capsule weight overstates the apparent loss unless the shell weight is accounted for separately.
The correct approach adds the shell weight to the target fill weight to get a theoretical filled capsule weight, then uses a separately measured actual average filled weight to convert the real output into a capsule count:
Theoretical filled capsule weight = Target fill weight + Shell weight
Actual capsules = (Total filled capsules weight × 1,000,000) ÷ Avg. filled capsule weight (actual)Losses here concentrate around capsules rejected for being under- or overweight during in-process checks, and fill material lost to dust collection or machine surfaces during the run.
Why stage-wise reconciliation is worth the extra effort
A single end-of-batch yield figure tells you that something went wrong, somewhere. Stage-wise reconciliation tells you where — and that distinction is the difference between a five-minute investigation and a half-day one. It also means each stage builds a track record over time: if compression consistently runs a slightly higher loss than granulation and coating, that's a signal worth acting on, whether it's press settings, tooling wear, or something in the formulation itself.
If you're doing these calculations by hand across a full batch record, they're a genuinely useful thing to have pre-built rather than re-derived every time. The Batch Reconciliation calculators on PharmainformCalc cover all four stages — granulation, compression, coating, and encapsulation — each set up exactly as described above, so you can drop in your own batch figures and get the loss and yield breakdown instantly.