Detecting Gradual Supplier Price Increases

There are two types of price increases. The one you're notified about via email ("effective May 1st, salmon prices will increase by 6% due to North Atlantic market changes") and the one that happens without anyone mentioning it: the price goes up by €0.15/kg this month, another €0.20/kg in three months, and another €0.25/kg six months later. A year on, what cost €8.40/kg now costs €9.40/kg, and you never had a conversation about it.

We call this a silent price increase. It's not illegal, and in many cases, it's not dishonest (supplier costs also rise), but it's in your interest to detect it early for two reasons: to be able to discuss it if you believe it's unjustified, and to adjust your menu or orders before your margins erode without your knowledge.

Why It's Hard to Detect with the Naked Eye

Three factors make silent price increases practically invisible if you only look at invoices:

1. Your monthly invoice doesn't change much. If your weekly order varies in quantity and product mix, monthly totals also vary for reasons unrelated to price. One month you order less fish and more vegetables. Another month there's an event, and you increase everything. This masks the real increases.

2. Checking unit prices line by line is exhausting. A monthly invoice with 80 lines from an active supplier, multiplied by 8-12 suppliers, means hundreds of prices per month. Nobody compares each one to the previous one.

3. Increases are small. A 2-3% increase is undetectable to the naked eye in a price. A 5% increase is noticeable if you look for it. A 10% increase is obvious, but by then, the increase has already been applied for some time.

What Does Work: Historical Data Per Product

The reliable way to detect silent price increases is to maintain a history of unit prices per product and supplier, and review the evolution each month (or every time you digitize an invoice).

For "Vine Tomato 1st Quality" from Supplier X, you should be able to see a time series of the price:

January: €4.80/kg
February: €4.80/kg
March: €4.80/kg
April: €4.90/kg
May: €4.90/kg
June: €5.10/kg
July: €5.10/kg
August: €5.30/kg

This history tells a story that no individual invoice can. And when an invoice arrives in September with tomatoes at €5.40/kg, you no longer need to wonder if it's right or wrong: you have the context.

Three Practical Signs to Watch For

Beyond the general historical data, there are three specific patterns worth learning to recognize:

1. The seasonal increase that doesn't drop back down.

Some products increase in price during specific seasons (fresh fish in winter, out-of-season fruit). The price goes up in December, January, February. That's expected. What's not expected is that in March or April, when the season ends, the price doesn't return to the usual range of the previous year. If you look at your historical data and see that each year the off-season price is higher than the previous year, there's a permanent upward drift camouflaged behind seasonality.

2. The brand or reference change.

Your supplier slightly changes the product name: it goes from "Extra virgin olive oil 5L" to "Premium extra virgin olive oil 5L". Same bottle, same oil, new label, 8% higher price. If your management system continues to treat it as a different product from the previous one, it won't detect the increase because there's no history to compare.

Solution: when a "new reference" appears from a regular supplier, check if it's truly new or the same product re-labeled. If it's the latter, merge them in your system so they continue to share historical data.

3. The diverging moving average.

Calculate the 3-month moving average of each product's price. If the moving average of the last 3 months is more than 5-7% above the moving average of the previous 3 months, there's an increase. This metric is more robust than looking month-to-month because it smooths out sporadic variations.

How to Automate It Without Going Crazy

Maintaining a manual history for 200-500 different products that a restaurant handles is unfeasible. Here are three options, ordered by increasing sophistication:

Option 1: Minimum Viable Excel. A workbook with one sheet per supplier. Each sheet: product, date, price. You manually enter prices each month. It takes a couple of hours monthly but gives you data. Useful if you have few suppliers and want to validate before investing.

Option 2: Purchasing Management Software. Specific tools for the hospitality industry that extract prices from invoices and archive them automatically. They provide product evolution graphs, price increase alerts, and supplier comparisons.

Option 3: OCR + Integrated Database. The fastest option and the one we recommend: each digitized invoice automatically feeds into a historical database, and any anomalous price change (beyond a configurable threshold) generates an alert even before you approve the invoice. This is what Sincrio does: it detects deviations against your own historical data, flags the document for review, and prevents a €0.30/kg increase on something you order every week from silently slipping through.

What to Do When You Detect One

Once you've confirmed that a supplier is increasing prices without notice, your options are:

1. Ask for an explanation. Call and ask why. Sometimes there's a legitimate reason (increase in origin cost, scarcity, new regulatory costs). Other times, the sales rep might say "I hadn't noticed" and fix it for you.

2. Renegotiate. If the reason doesn't convince you, state your case: "The price of X has increased by 8% in the last six months without us discussing it. I need it to return to Y, or I'll have to look for alternatives." Negotiations where you come armed with data usually go well.

3. Compare with the market. Request quotes from one or two alternative suppliers for the same product. Sometimes what your regular supplier considers a "market-driven increase" isn't so mandatory.

4. Change suppliers or diversify. If the conversation yields no results and the increase represents a material cost, moving part of your volume to a competitor is a legitimate response. A credible threat is often enough for the supplier to reconsider.

5. Pass it on to the menu. If you've exhausted your options, the last resort is to pass the increase on to the dish price. However, this should be a last option, not a first reaction, because every menu price increase has its own image cost.

Conclusion

Silent price increases are one of the most common forms of margin erosion in the hospitality industry. Most operators don't detect them because they don't compare unit prices against historical data, and the final monthly figures seem normal.

What you need is a history of prices per product and supplier, and to review it (or have something review it for you) systematically. When you detect an increase, you can almost always do something about it. What you don't detect in time, you end up paying for.