How to Use a Conical Fermenter

Step 1

Fill to 75-80 percent, not to the brim

Krausen needs room. Fill a conical to roughly three quarters of its total capacity -- 5 to 5.5 gallons in a 7 gallon vessel -- and you have the headspace a vigorous fermentation needs. Fill it higher and the krausen goes into the airlock, which blocks it, which pressurizes the vessel, which is a mess at best.

If you must fill higher, fit a blow-off tube into a jar of sanitizer rather than an airlock, and expect to clean it.

Step 2

Dump the first trub fraction at 24-48 hours

This is the step people skip, and it is where the cone starts earning its price. Within the first day or two of active fermentation, cold break, hop particulate and the first dead cells have settled into the cone. Open the dump valve briefly and let that fraction out -- usually a cup or so, until what comes out stops looking like sludge.

• Sanitize the valve first. Spray it, inside and out. You are opening a path into the vessel mid-fermentation.
• Open briefly and close. You are removing sediment, not beer. Stop as soon as the flow turns from sludge to liquid.
• Do not dump during the first 12 hours. The yeast is still distributing; let it get going first.

Step 3

Harvest yeast at the end of fermentation

Once gravity has been stable for 48 hours, the yeast has flocculated into the cone and the second fraction is clean, viable slurry.

1. Sanitize a jar with a sealing lid, and sanitize the valve.
2. Draw off a small amount first and discard it -- that clears the valve body and any remaining trub.
3. Collect the slurry into the jar. You want a creamy, uniform layer rather than anything dark or granular.
4. Seal loosely (it will still off-gas), refrigerate immediately, and pitch within two weeks. Viability falls off after that.

Full reasoning on why harvested slurry often outperforms a fresh pack is in why use a conical fermenter.

Step 4

Cold crash for 48 hours

Dropping the beer to 32-38°F for a couple of days pulls remaining yeast and protein out of suspension, which gives you a visibly clearer beer in the keg. On a conical the sediment collects in the cone where it is out of the way.

Step 5

Transfer: under CO2 if you can

Pressure-rated vessel

Purge the receiving keg with CO2 (fill it with sanitizer and push the sanitizer out with gas, or flush several times). Connect the fermenter’s liquid post to the keg’s liquid post, apply a few psi to the fermenter, and vent the keg’s gas post. The beer moves across without meeting air at all. See how to pressure ferment.

Non-pressure vessel with a racking arm

Rotate the arm to just above the sediment line, sanitize the valve and tubing, and run the beer into a purged keg. Keep the tubing full and the outlet below the liquid surface in the keg to minimize splashing. You will pick up some oxygen -- that is unavoidable -- but a short, gentle transfer picks up far less than a long splashing one.

Step 6

Clean immediately, not tomorrow

The single biggest determinant of how long a fermenter lasts is how soon you clean it. A krausen ring rinsed off while fresh takes two minutes; the same ring dried on for a day takes scrubbing, and scrubbing is what destroys plastic vessels and scratches polished stainless.

• Rinse with warm water immediately after transfer.
• Soak with a non-caustic alkaline brewery wash, warm, 20-30 minutes. Stainless tolerates caustic; PET does not.
• Dismantle the fittings. The valve, the racking arm and the lid gasket are where soil hides. Flushing is not cleaning.
• Rinse, dry, and store with the lid off so it does not go stale.