Choosing serving tanks or kegs for a brewpub bar

Two ways to feed a tap

A serving tank is a pressure-rated vessel, often 250 to 1,000 litres, sitting in a cold room behind or above the bar. Beer is transferred into it from the bright tank or straight from the fermenter after filtering or conditioning. A line runs from the tank to the tap. Nobody lifts anything.

A keg is a portable stainless container, usually 20, 30 or 50 litres in India, filled in the brewery and connected to the tap with a coupler. When it blows, someone swaps it. Kegs also let beer leave the building, which matters if you ever plan to supply other bars.

Volume decides first

The deciding number is how fast each beer sells. A serving tank works best when it empties within about two to four weeks. If your house lager sells 400 litres a week, a 1,000 litre serving tank is ideal. If your seasonal stout sells 60 litres a week, the same tank would hold it for four months. That is too long for most beers and it locks up a tank you could use elsewhere.

A simple rule we use: put your two or three best sellers in serving tanks and pour everything else from kegs. Look at your sales by beer, not your total. Our guide on brewpub layout shows where each option fits in the floor plan.

What serving tanks do better

• Labour. No keg filling, no keg washing, no changing kegs on a Saturday night.
• Freshness and oxygen. Fewer transfers mean fewer chances to pick up oxygen. Every transfer is a risk. Hop-forward beers punish it hardest.
• Less loss. Kegs leave beer behind at every change and every fill. Big tanks lose less per litre.
• Theatre. Tanks visible behind glass sell beer. Guests like to see where the pint came from.

The catch is space and cooling. Tanks need a cold room held at around 2 to 4 °C. They also need careful CO2 top pressure, because the beer sits in the tank for weeks and will lose or gain carbonation if the pressure drifts.

What kegs do better

• Range. Twelve taps from twelve kegs costs far less than twelve tanks.
• Flexibility. A keg can go to a festival, a corporate event or a second outlet where your state's rules allow it.
• Smaller batches. A 200 litre trial brew fills a handful of kegs and is gone in a week.

The cost is in people and equipment. You need enough kegs to cover beer in the cold room, beer on tap and kegs being washed. You also need a keg washer or a careful manual routine, couplers and spare seals. Our page on buying craft beer kegs covers sourcing.

Pressure and temperature still rule

Whichever you choose, the tap pours only as well as the gas balance behind it. Most craft lagers and ales are served at around 2.4 to 2.6 volumes of CO2. At 3 °C that needs a top pressure of roughly 0.8 to 1.0 bar. Long lines to a distant bar need extra pressure or mixed gas to push the beer without overcarbonating it.

In an Indian summer, the weak point is often the line run from cold room to tap, not the tank. If the python is poorly insulated, the first pour of every round comes out foamy. That is lost beer you paid duty on.

Costing the choice properly

Put both options on one sheet. For tanks: vessel cost, cold room space, CIP time and the beer lost when a tank is emptied. For kegs: number of kegs, washer, labour hours per week and beer lost at each change. Run it over five years, because kegs and tanks both last much longer than a year. Founders often compare only purchase prices, then discover the labour bill a year later.

Cleaning and changeover time

Both systems need cleaning, but the work lands differently. A serving tank is cleaned in place between fills: caustic, rinse, acid or sanitiser, then a CO2 purge before the next beer goes in. That is a few hours of tank downtime every few weeks. Kegs are cleaned every single time they come back, so the work is small but constant.

Lines are the same either way. Beer lines need cleaning on a fixed routine, commonly every one to two weeks, or yeast and bacteria build up and every beer starts to taste the same. Put the line-cleaning schedule on the wall before you open, whichever system you choose.

Where to start

Pull a month of sales by beer. Any beer selling enough to empty a serving tank in three weeks is a candidate for one. Price that tank. Everything else goes in kegs. Revisit the split every six months, since your menu will change faster than your tanks.

Common questions

How long can beer sit in a serving tank?

Aim to empty a serving tank within two to four weeks. Many beers will hold longer under good CO2 pressure and cold, but hoppy beers fade and the tank is better used for a faster seller.

What temperature should a brewpub cold room run at?

Around 2 to 4 °C for serving tanks and kegs. Colder holds carbonation better and slows staling. The beer can warm slightly in the glass before it reaches the guest.

Can I use both serving tanks and kegs?

Yes. Most brewpubs do. Best sellers go in serving tanks and smaller or seasonal beers go in kegs.