Yogurt scales cleanly, because it's milk and culture and the culture does the work: write the milk, milk powder and culture as percentages, heat the milk in a vat, cool it to incubating temperature, add the culture, and hold it until the pH falls to about 4.6. The care is in the temperatures, and in the dairy plant license that yogurt for sale is made under. Done this way, a yogurt maker that made a gallon at a time makes about 215 quart tubs from a 50-gallon vat, and the cost of a tub falls from $10.79 to $2.58. Below is the recipe at two sizes, the steps, the loss, what a tub costs at each size, and a free scaling calculator.
The short version
- Write milk, milk powder and culture as percentages.
- Heat the milk in the vat, about 185°F held 30 minutes in the example.
- Cool to about 110°F before the culture goes in.
- Incubate until the pH reaches about 4.6, then cool fast.
- Yogurt for sale is made in a licensed dairy plant.
- Weigh what comes out and use your real loss to cost a tub.
- TaroStack keeps the recipe by weight, takes each batch's ingredients off stock and checks its yield. More below.
The recipe, by percentage
Laurel Fork Creamery, the made-up yogurt maker in Floyd, Virginia, I use in these examples, tested its recipe a gallon at a time before its 50-gallon vat pasteurizer was licensed. The recipe, weighed:
| Ingredient | % of the mix | Kitchen batch, 8.6 lb | One batch, 440 lb | The run, 440 lb | Cost a lb, bought in bulk |
|---|---|---|---|---|---|
| Whole milk | 97% | 8.34 lb | 426.8 lb | 426.8 lb | $0.41 |
| Nonfat dry milk | 3% | 0.26 lb | 13.1 lb | 13.1 lb | $3.00 |
| Yogurt culture | 0% | 0.00 lb | 0.09 lb | 0.09 lb | $350.00 |
| The whole mix | 100% | 8.6 lb | 440 lb | 440 lb |
The 440 pounds cost $243.84 in ingredients, nearly all of it milk at $3.50 a gallon. The culture is two ten-thousandths of the weight; a pouch dosed for the vat, not a spoonful of last week's yogurt. The tubs are in how to package yogurt for sale.
The steps, at 440 pounds
- Fill the vat by weight. Milk in, milk powder whisked in for body.
- Heat and hold. About 185°F for 30 minutes in the example, which pasteurizes the milk and thickens the finished yogurt; the vat's chart records it.
- Cool to 110°F. Through the vat jacket, stirred.
- Add the culture. The pouch dosed for the vat's volume, stirred in.
- Incubate. Held at temperature until the pH reaches about 4.6, often four to six hours, tested every half hour near the end.
- Cool fast and fill. Chilled to 40°F, fruit stirred in for flavored batches, filled into tubs.
- Label with a lot code. Every tub carries the vat's lot and its date.
The run takes about 10 hours of labor, with cleaning the vat and filler.
What a tub costs at each size
| Per tub | Kitchen batch, 8.6 lb | Bulk run, 440 lb |
|---|---|---|
| Ingredients | $2.76 (grocery prices) | $1.13 (bought in bulk) |
| Packaging | $0.70 | $0.52 |
| Labor at $20 an hour | $7.33 (22 min a tub) | $0.93 (2.8 min a tub) |
| Cost of a tub | $10.79 | $2.58 |
Milk by the bulk tank instead of the gallon jug cuts the ingredients by more than half, and the labor falls from 22 minutes a tub to about 3. The margins by product are in yogurt profit margin, and the year in yogurt business plan.
The dairy plant
Yogurt sold to the public is made from pasteurized milk in a dairy plant licensed by the state's dairy program, with the vat's time and temperature charted on every run; a home kitchen can't make it for sale. The label's "yogurt" means the standard: cultured with the two named bacteria from pasteurized dairy ingredients.
Get the calculator
Download the yogurt scaling calculator. Two sheets: scale the recipe, where you type each ingredient's percentage and cost a pound and the raw mix you want, and each ingredient's weight for the run fills in, with the vat runs, what comes out after the vat loss, the tubs it fills and the cost of each tub; and weigh the loss, where what went in and came out over a few batches gives your average vat loss. It's an ordinary Excel file with no macros, and it works in Google Sheets, LibreOffice and Numbers.
Where this stops working
Plain, vanilla and Greek, vats three days a week, milk from two dairies, and a grocer asking about one tub. A sheet can say how much milk powder a run needs, but not which dairy's milk went into which vat, or how many tubs are left before their date.
How TaroStack does it
TaroStack keeps the recipe by weight, takes each batch's ingredients off stock and checks its yield.
The recipe in the units you use. A recipe holds each ingredient by weight, with milk bought by the bulk tank and used by the pound, and the cost of every tub comes from what you paid. "What could I make right now" says how many runs the milk, milk powder and culture on the shelf allow.
Each run a batch. A run takes its ingredients off stock, records the lots of milk and culture it used, and gets a lot of its own for the tubs, with how much came out good, how much was rejected and the labor minutes.
Yield checked from history. From your own batch history, TaroStack says whether a recipe yields what it claims and which ingredient's quantity is off, so a vat loss that creeps up shows in the numbers. A tank of milk rejected at receiving is an adjustment with its reason, spoiled, and shows in the waste report.
| The job | Spreadsheet | In TaroStack |
|---|---|---|
| Ingredients for Tuesday's run | Multiply, then check the shelf | What could I make right now |
| Which milk went into a run | Not written down | Lots recorded on the batch |
| The real vat loss | Weighed now and then | Good and rejected on every batch |
| Milk rejected at receiving | Thrown out, forgotten | Adjustment with a reason |
Recipes, batches, lots and yield are on every plan, from $49 a month. The first 30 days are free, with no credit card. If you'd like a hand setting up, ask, and we'll do it with you.