We have had more than few users inquire about what volume the chill coil starts at and how full their Chronicle needs to be filled to achieve effective cooling. For example, a user that purchased a 14 gallon BME Chronicle but wants to do the occasional 5 gallon batch can probably expect roughly 35-40% of contact if 6 gallons of total volume make it into the fermenter. Which would in most cases works great for holding ale fermentation temperatures.
Yet, keep in mind that the time it takes to effectively chill the beer may vary based on ambient temperatures. Furthermore, we recommend that users avoid more advanced lagering or crash cooling activities with smaller batches since it will put additional stress on the chill water source to achieve such a low relative temperature.
If you plan on using your Chronical often for partial batches, it may be better to use a flat lid mounted coil with coil extensions for better surface area contact, in that case a standard series Chronical with FTSs system would be a better choice. Users that are still unsure which route they should ultimately take, a BME Chronical or a standard series Chronical, keep in mind that we will be providing the necessary upgrades as separate accessories to convert a standard Chonical to a BME Chonical. We did this so users didn't have to sacrifice features to customize their vessel to their own individual needs.
Here are the measurements for each size and the corresponding liquid volume where the chill coil begins and ends:
7 gal - 3.75-6.50 gal
14 gal - 4.00-10.75 gal
Half bbl - 5.00-13.75 gal
1 BBL - 12.00-34.00 gal