Shopify for coffee roasters: why the bag count is lying to you

Shopify's inventory engine was built for people who buy a widget and sell a widget. You buy green coffee and sell roasted bags, with a roast loss in the middle and sometimes a blend on top. The native inventory model fights you on all three. Here is what breaks and how to fix it without rebuilding your store.

The three mismatches

• Shopify tracks finished bags; your purchasing decisions are about green lbs.
• Shopify has no concept of blend ratios; your house blend is 60/40.
• Shopify does not know that a 12 oz bag is 14.3 oz of green; it thinks 1 sold = 1 deducted.

What roasters usually do (that doesn't work)

The most common fix is a spreadsheet, updated weekly, that subtracts green 'by hand' based on sales. It works for about three months and then drifts — someone forgets a week, a blend ratio changes, a roast profile gets adjusted. By month six the spreadsheet and the physical inventory disagree by enough to matter.

What actually bridges the two

• Map each Shopify product to one or more green lots, with ratios.
• Attach a roast profile to each product (which sets the loss %).
• Listen to the orders/paid webhook and deduct the correct green ounces, per lot.
• Surface both numbers to the roaster — Shopify bag count AND underlying green lbs.

Done right, you keep Shopify as the source of truth for what customers see, while your green inventory stays automatically accurate underneath. No reconciliation. No weekly spreadsheet. No end-of-month surprises.