Brewery and Distillery Heat Exchangers

Wort cooling, wine must, distillation and mash

Wort cooling is a fixed-time problem. The kettle holds 10 to 300 barrels and the brewer wants it knocked out in 30 to 60 minutes, so the flow rate is the batch divided by that time and the exchanger is sized on it. The first stage on brewing water at 55 to 65 F takes the wort from 212 F to 75 to 85 F and heats the water to 170 to 180 F, which is the next brew's hot liquor; the second stage on propylene glycol at 28 F finishes to 50 to 55 F for lagers or 65 to 68 F for ales. Getting through 160 F to pitching quickly keeps wild yeast and bacteria from establishing, drives off dimethyl sulfide, forms a good cold break and holds late-hop aroma, which is why a single-pass chiller beats a jacketed tank for every brewery above pilot scale.

Wine must is a solids problem. Crushed grapes carry skins, seeds and pulp, and cold soaking red must at 45 to 50 F for several days before fermentation, then warming it to 60 to 85 F to start the yeast, means an exchanger that passes seeds without blocking. Wide-gap plates do it for most must; whole-cluster or heavily extracted must goes through a tube-in-tube with a 2 inch bore. White juice after pressing is clear and runs on standard plates to 45 to 50 F for settling. Tartrate scale from the acid step and pigment from red skins mean the CIP program is caustic, acid, then a citric rinse, and the product side is 316L.

Distillation is a vapor problem. A pot still or column boils at a rate set by the steam or heat input, and the condenser has to take every pound of that vapor plus the non-condensables to liquid at the collection temperature. The condenser is a vertical shell-and-tube with vapor in the tubes and cooling water on the shell, vented at the top and drained at the bottom, sized on the boil-up rate at the lowest cooling water temperature the plant sees. A dephlegmator is the same construction placed at the top of a column and run with throttled cooling water so that part of the vapor refluxes; its surface area sets the maximum reflux ratio, so it is sized generously and controlled by water flow. Copper tubes are chosen by distillers who want sulfur removal; 316L by those who want a neutral spirit.

Mash in a distillery is thick with grain. Cooling grain-in mash from 150 F to 85 F for fermentation runs through a multi-tube or single tube-in-tube at low velocity with hot water recovered on the utility side. A wash cooler after the beer still is a plate exchanger because the wash is clear by then. Every distillery also runs a steam-to-water U-tube set that feeds still jackets, mash tun heating and CIP; sizing it on the coincident peak is what keeps the second still from starving the first.