n8n Workflow: Track Menu Cost Ratios from Delivery Notes

Automatically track menu cost ratios from delivery note photos—so you spot loss weeks earlier

This n8n workflow monitors delivery notes, extracts supplier pricing with Google Gemini, keeps your Google Sheets ingredient prices up to date, and calculates each menu item’s current cost ratio against its target. If any dishes run over target, it generates exactly three practical actions per dish and emails them to you—no guesswork.

What this workflow does

• Triggers daily at 8:00 or when a new delivery-note photo is created in a specified Google Drive folder.
• When a new photo is detected, it downloads the image and uses Google Gemini to extract supplier, date, totals, and line items as structured JSON.
• It converts invoice quantities into base units (per gram/ml/piece), then verifies line items against the printed subtotal/total. If totals don’t match, it either updates automatically or emails you to manually check the photo.
• On the daily run, it reads your Ingredients, Recipes, and Menu tabs in Google Sheets, calculates each dish’s theoretical cost, current cost ratio, and status vs target, and writes the latest values back to the Menu tab.
• If any dishes are over target, it sends the over-target facts to Google Gemini, generates three concise actions per dish, and emails the results via Gmail. If nothing is over target, it sends no email.

Use cases

• Restaurants and meal services tracking margin drift as ingredient prices creep up.
• SaaS operators or ops teams validating menu costing and cost ratio targets without manual spreadsheet updates.
• Automation engineers building a reliable invoice/photo-to-costing pipeline with Google Sheets reporting.

Technical details

• n8n logic uses: if, set, code, switch, and no op, plus Gmail for notifications.
• Integrations: Google Drive (delivery-note photos), Google Gemini (extraction + actions), and Google Sheets (Ingredients/Recipes/Menu tabs, including target_cost_rati… fields).