Rainwater Wort Cooling (#homebrew)

Sittin' here nursin' an Espresso Stout and considering the viability of collecting rainwater into underground storage tanks for the purpose of cooling wort.

Imagine the brew-house structure's rain downspouts directing rainwater into a large storage tank or tanks, with overflow optionally to a second tank or tanks. Another or other tanks are always empty, but need not be.

On brew day, to cool the wort, pump rain water from a source tank containing cold water, through the heat exchanger (chilling the wort) and into a destination tank which is initially empty or nearly so and slowly fills with the now warm water.

After a suitable time when the warm water has had a chance to cool, use that tank as the source for the cold cooling water for the next batch, pumping it through the heat exchanger to a destination empty tank. Repeat, swapping tanks.

Switching source and destination tanks could be a manual operation using valves.

There is no harm in filling all available tanks with rainwater and simply directing the downstream warm water into a pond or using it to irrigate, say, the hop yard. It could also be used for animal drinking water.

Of course, tank sizing is important and depends on the temperature of the stored cold water and the batch sizes.

Underground tanks should be buried based on the local climate, to ensure cool water for summertime brewing, although storing the water higher than the brew-house and using gravity to feed the heat exchanger should be investigated.

Underground tanks in freezing climates must be buried under the frost line to ensure liquidity.

Fiberglass or plastic tanks would be preferable so that they last a long time. The tanks don't store potable water but simply cooling water--hence clean-outs would be nice but not absolutely necessary.

There is a brewery in Georgia, 5 Seasons Brewing Company, that has a rainwater catchment system.

It would be beneficial to investigate their system for other ideas.

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