Run a one-venue cocktail keg trial

Choose one measurable problem

Pick one drink and one venue. Write the problem as an observable result: orders waiting during the rush, time spent preparing the base, inconsistent measures or unsold batch disposal. Record the existing process before changing it.

• Choose matched baseline and trial shifts with comparable staffing and demand.
• Set a finished pour size, spirit brand and menu price for both methods.
• Keep the recipe, glassware and garnish fixed unless a change is itself the trial question.

Record the inputs that determine cost

• Keg invoice and freight, or actual ingredients used for the in-house batch.
• Spirit volume and bottle size: 9 L requires twelve 750 mL bottles.
• Finished liquid volume, selected pour size and measured waste.
• Preparation, filling, changeover, service and cleaning minutes, plus the actual loaded labor rate.
• Menu sales, discounts, refunds and any unsold product.

Calculate on the same serving basis

Gross pours = finished liters × 33.814 ÷ finished US fl oz per pour. Saleable pours = gross pours less measured loss, rounded down. The 29 L standard build gives about 245 gross 4 oz pours, 163 gross 6 oz pours or 122 gross 8 oz pours. The 19 L build gives about 160, 107 or 80 respectively.

• Spirit cost = added milliliters ÷ bottle milliliters × bottle price.
• Ingredient and freight cost per saleable drink = total mixer, spirit and freight cost ÷ saleable drinks.
• Labor cost = total process minutes ÷ 60 × loaded hourly rate.
• Contribution before overhead = realized drink revenue minus ingredients, freight and measured labor. This is not net profit.

Worked example: a 30 L Margarita vessel

Illustrative inputs, not a customer result: $155 mixer keg, 9 L tequila, twelve 750 mL bottles at $25 each, $0 freight and a 4 oz finished pour. Mixer plus spirit is $455. Gross yield is about 245. With an assumed 5% loss, round down to 232 saleable drinks: about $1.96 ingredient cost per drink. At $12 each, ingredient contribution is $10.04 per drink before freight, labor, garnish, tax and overhead.

Replace the $25 bottle price and 5% assumed loss with your invoice and trial measurements. Compare the same calculation against your batch ingredients. We have not assumed that either method is always cheaper.

Measure the whole service

• Time complete orders from order entry to handoff; record tap-pour time separately.
• Count completed drinks during the same-length rush interval. Note order mix and staffing.
• Record preparation, replenishment and cleaning time outside the rush.
• Measure discarded liquid and reconcile expected pours with sold drinks.
• Ask guests and staff the same taste and usability questions in both periods. Record exceptions, including failed checks.

Decide whether to repeat, change or stop

Agree the thresholds before reviewing the results. A draft trial may improve the bottleneck while adding a new cleaning or storage constraint. An in-house batch may remain the better fit for a rotating or low-volume drink.

• Expand only when the recipe, equipment checks, service results and cost case pass at the pilot venue.
• For a second site, repeat commissioning and recipe sign-off; do not assume every line is identical.
• Keep a written reason if you stop the trial. A stopped trial is useful evidence.
• Publish a named case study only with the operator’s approval and actual measurements.