Cool Brewing Fermentation Temperature Control Bag - Insulated Cooler for Fermenters to 40L
The Cool Brewing bag solves summer fermentation without a fridge, a chamber or a single watt of power: a heavy-duty insulated cooler bag that swallows fermenters up to 40 litres — bucket, carboy or small conical — and holds them at ale temperature on nothing but a couple of frozen bottles. Drop the fermenter in, add ice bottles beside it, zip it shut, and swap the bottles once a day; a heatwave brew day stops being a gamble.
It works the other way too: in a cold garage, the same insulation holds fermentation warmth in. The side zipper gives access for samples and gravity readings without unpacking, and after the batch the whole bag folds flat for storage. Internal 52×67cm — the Brewferm 30L bucket and most 30L fermenters fit with ice-bottle room to spare.
Key features
- Insulated bag for fermenters up to 40L — no power needed
- Ice-bottle cooling: swap daily, hold ale temperatures through summer
- Also retains warmth in cold rooms
- Side zipper for samples without unpacking
- Folds flat between batches
Quick facts
- Brand: Cool Brewing
- Type: fermentation temperature control bag
- Fits: fermenters up to 40L (internal 52.1 × 67.3cm)
- Cooling: frozen bottles, replaced daily
- Use: summer fermentation, temperature stability, cold-room brewing
Related products
- RAPT Fermentation Chamber — the powered, automated alternative
- Grainfather GF30 Fermenter Coat — the fitted-jacket approach for conicals
- 30L Fermentation Vessel with Airlock & Tap — the bucket this bag was practically made for
- RAPT Pill — reads the temperature inside without opening the zip