Spirit Safes How it works
The stillman can't taste or nose the spirit during distillation but has to rely on hydrometers, optical observation and experience from the outside of a locked spirit safe. When the alcohol content comes down to 59-67% the lever or knob is turned once again. When this is done vary from distillery and the type of spirit produced and peatiness. Painting of Spirit Safe by Talaat Elshaabiny 2010
The drawing made is based on a sprit safe made by Archibald McMillan & Co Ltd serving two stills. Spirit safes from other manufacturers look different and have more compartments if they serve more than two stills. However the working principle is identical.
On the backside there are two inlets -
from the LOW WINES STILL
from the SPIRIT STILL
The spirit safe has three compartments:
On the bottom side there are four outlets:
to the LOW WINE RECEIVER
to the FEINTS RECEIVER
to the SPIRIT RECEIVER
to the DRAIN
On the top there are lids, locked with two padlocks at either sides or with just one padlock depending on design.
There is also a knob on the top where the direction of the flow from the second distillation can be changed.
Ventilators are placed also placed on the top.
LOW WINE COMPARTMENT
The spirit from first distillatiion flows into a glass bowl.
The bowl has a hole in the bottom and flows to the low wines and feints receiver. This takes about 4 hours. Samples of the low wine for measuring of the alcohol content is taken by turning one of the small knobs on the front side. The low wine has an alcohol of about 20-21 % and is distilled a second time together with feints from second distillation. The alcohol content is between 25-30 %. It should not exceed 30% as it will result in "blank run".
The spirit from the second distillation "spirit run" flows into the middle
compartment. The head (foreshot) runs for about about 10 minutes
(but can vary from 5 - 45 minutes) and is to strong about 80 % and contains undesirable components. The alcohol content is measured in the same way as above but the measuring is more critical.
When the alcohol content decreases to around 74-75% the knob or lever at the top of spirit safe is turned. The spirit flow is now directed to the next bowl and goes to the spirit receiver.
This is called the middle cut or the "heart".
The flow from the"tail" is re-directed to the second bowl and into the feints receiver.
Samples from both distillations are taken.
By turning one of the small knobs on the front side a glass test tube is filled with
spirit and the alcohol content from the wash still is measured with a hydrometer.
The hydrometer used is calibrated at 20 C in the full range 55-80% ABV or with a narrow range hydrometer 0-6 % ABV.
More measurements are made on the spirit from the second distillation. Two glass test tubes are used for this and both have hydrometers. One has also a thermometer in the glass test tube. In the other water is added to the test tube for the demisting test. In this test the sprit in the test tube is diluted with water until it reaches 46 % and the stillman looks at it. The foreshot spirit gives a cloudy solution but the middle cut spirit is unaffected when water is added.
The hydrometer in the first test tube for the spirit run is scaled 0-6 and in the second 55-80. Based on these measurements the cutting points are decided, i.e when the middle cut starts and end. The time it takes is also registered and the heat applied affects the speed.
The stillman decides when the make the cut. The spirit is normally diluted to 63.5% and then filled on cask. The reason is for quality reasons by maturing but also historical as it made trading casks much easier.
Please join the "Spririt Safes Collectors Club" on Facebook
Inge Russell a.o. "Whisky: Technology, Production and Marketing (Handbook of Alcoholic Beverages)"
Per Ellsberger "Skotsk whisky: allt om maltwhisky - historia, tillverkning, destillerier"
Roger Melander - Distillery Manager Box Distillery
Special thanks to my son Charles who helped me when I made the 3D drawing in Google Sketchup.
The stillman can't taste or nose the spirit during distillation but has to rely on hydrometers, optical observation and experience from the outside of a locked spirit safe.
When the alcohol content comes down to 59-67% the lever or knob is turned once again. When this is done vary from distillery and the type of spirit produced and peatiness.
Painting of Spirit Safe by Talaat Elshaabiny 2010