When a manufacturing order is produced, the components it used have to be recorded as consumed. There are two broad ways to do that, and backflushing is one of them. This piece explains backflushing component consumption in Odoo.
The two ways to record consumption
When production happens, components are physically used, and that consumption has to be reflected in the system, the component stock has to go down. There are two broad approaches. One is to record consumption explicitly: as components are used, their consumption is actively recorded. The other is backflushing: rather than recording each component's consumption by hand, the system records the consumption automatically, derived from the bill of materials, when production is completed. Backflushing, in essence, says: this manufacturing order produced this quantity, the BOM says that quantity requires these components, so record those components as consumed.
What backflushing is
Backflushing is the automatic recording of component consumption based on the BOM and the quantity produced. The name captures the idea: rather than tracking each component into production as it goes, the consumption is "flushed back" through the BOM after the fact. When the manufacturing order is completed, the system works out, from the BOM and the produced quantity, what components were used, and records that consumption. The manufacturer does not record each component's consumption individually; it is derived.
Why backflushing helps
Backflushing helps by reducing the effort of recording consumption. Explicitly recording the consumption of every component, on every manufacturing order, is work, and for a product with many components, or a plant with many manufacturing orders, it is a lot of work. Backflushing removes most of that: the consumption is recorded automatically from the BOM, so the floor does not have to record each component individually. For production that is straightforward and consistent, where the components used genuinely are what the BOM says, backflushing is an efficient way to keep component stock correct without a heavy recording burden.
When backflushing is appropriate
Backflushing rests on an assumption: that the components consumed are what the BOM says they are. That assumption is sound when production is consistent, the BOM is accurate, and what actually goes into the product reliably matches the BOM. For such production, backflushing is appropriate and efficient: deriving consumption from the BOM gives the right answer, and it saves the effort of recording each component.
Where the assumption is weaker, backflushing is less appropriate. If actual consumption genuinely varies from the BOM, more or less of a component used than the BOM says, in a way that matters, then deriving consumption from the BOM will not reflect what really happened. Production where consumption genuinely varies, or where the manufacturer needs to capture exactly what was used, including which specific lots, may need explicit recording of consumption rather than backflushing, or backflushing with the variations captured. A manufacturer should choose backflushing where the BOM genuinely reflects consumption, and explicit recording where it does not.
Backflushing and BOM accuracy
An important consequence: because backflushing derives consumption from the BOM, backflushing makes BOM accuracy even more critical than it already is. If the BOM is wrong, and consumption is backflushed from it, then the recorded consumption is wrong, and the component stock figures drift away from reality, silently, because nobody recorded the real consumption to catch the discrepancy. A manufacturer using backflushing must keep its BOMs accurate, because the BOM is now directly driving the inventory records of component consumption. Backflushing on accurate BOMs keeps stock correct efficiently; backflushing on wrong BOMs quietly corrupts the stock figures.
The takeaway
Backflushing component consumption in Odoo records the components a manufacturing order used automatically, derived from the BOM and the quantity produced, rather than each component being recorded by hand. It helps by reducing the effort of recording consumption, and it is appropriate where production is consistent and the BOM genuinely reflects what is consumed. Where consumption genuinely varies from the BOM, explicit recording may be needed instead. Because backflushing derives consumption from the BOM, it makes BOM accuracy critical. For how we approach Odoo for manufacturers, see our manufacturing work.