'A Chilling Night At The Speedway'

Trial Description: Prior to beginning this trial , all thermometers were calibrated using the crushed-ice-in-water method. The calibrated thermometers were then used to verify correlation of the temperature read water directly in the hot liquor to the temperature read in the temperature well. The thermometers agreed within their Accuracy. This was done with separate thermometers as well as with singular thermometers no negate method of temperature measurement as a perturbation to this experiment.

Two 'identical'* five gallon batches of nutbrown ale were prepared from extract, each in its own kettle. The immersion chiller was dropped in the pot and the counter flow was set to recirculate boiling wort during the final 15 minutes of the boil (sanitation). * Counterflow batch suffered a boil-over. Less than a pint was lost.

Water was 'Y'ed from a single source. Water input temperature was measured to be 57°F. This measurement was repeated several times prior to running the chillers to ensure its stability.

At flame out, the temperature of at each kettle was recorded, and the temperature of the input water was reverified.Water flow was started at each chiller by means of a single valve.

The counterflow was initially set to return wort to the brew kettle in order to cool its coils following the boiling wort sanitation recirc. As soon as the water outflow from the counter flow chiller was cool to the touch, (this time was roughly 30 seconds, and is shown on Figure I) the aeration cane assembly was attached and affixed to the waiting fermenter. Flow through the aeration cane was slowed to provide maximum air draw. (Slow fill rate.)

The immersion chiller immediately began chilling wort. The kettle pump was set to gently recirculate wort over the coils under the liquid level, and the wort was stirred regularly. The kettle remained covered most of the time to avoid the introduction of airborne contaminants.

Samples for temperature checks taken in a heavy plastic 'beaker-on-a-stick'. Temperature readings were taken quickly to avoid heat loss or gain at surface (beaker thickness insulates side and bottom). Temperature/SG samples were not aerated.

Note: To keep the flow rate of water through the immersion chiller constant, water continued to run through the counterflow chiller after it had completed chilling of its batch.

DATA: Temperature Corrected OG: CF: 1.043IM: 1.038 Expected: 6.16lbs x 40 / 5 1.04928 Boil Volume: 7gFinal Volume: 5 gal (Brewer's Workshop predicted 1.044)

     Time (t)          Batch          Water Input  CF Water Output  
       mins  Counterflow   Immersion    Temp ºF        Temp ºF   
         0       212          212         57             57 
        0.5      106          203         57            106  Immersion chiller outlet
         3        68          180         57             68  temp was not measured.
        12        68          90          57             68
        18        68          80          57             68
        24        68          75          57             68
        29        68          75          57             68
        34        68          74          57             68
        35        68          74          57             68
        71                    74          57             68

Notes: Wort was cooled and aerated upon completion with counterflow. Another 36 minutes were required to transfer wort through aeration cane from immersion chilled tank.

Counterflow chiller was cleaned by circulating clean water through it. Immersion chiller required additional manual cleaning to clear break material from on and between the coils.

Counterflow pumped break material directly to fermenter as a matter of course. Little was formed. Immersion chiller pumped 1.25 inches of break material into fermenter. Break material clogged 50% of the aeration holes and developed back-pressure at outlet resulting in a wort sprinkler. Final fill was done without aeration. (Not a concern if you do not have a central siphon. Or brew in the dark. =)

Immersion-chilled sample at high kraeusen within 11 hours. Counter flow-chilled sample in active ferment; not yet at high kraeusen. (Same type/brand and quantity of yeast pitched in each: 2 sachets pitched dry; CF-chilled sample pitched 30 minutes prior to immersion-chilled sample.)

Both fermenting strong at 20.5 hours. Very turbid. Large solids (cold break) apparent in currents set up by fermentation. By 25 hours, kraeusen begins to subside. Blow-off tubes clear of foam. Approximately 1/2 gallon of blown off beer in blow off jar. (Typical for recipe.)

Particulars:

• Immersion chiller design:
  50' - 1/2" ID copper tubing. Cooling water enters coil at the top; exits at bottom. Home-made.
• Counter flow chiller design:
  20' - 3/8" ID copper tubing inside 3/4" ID flexible PVC hose (Qest). Wort flow counters water flow. Home-made.
• Brewing system:
  1/2 barrel kettles ala pico brewing systems. Fired by Kajun Cookers (Rocket Tubes) March Pumps. Drilled racking cane through orange carboy cap (aeration system).

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(C)1995 BabsTech Enterprises

Last updated 11/11/95