Developing a Birectifier Heating Routine

For sale: birectifier ($900USD)

We are getting more birectifiers in the wild so I thought I should write a guide to running it for the first few times to develop a heating routine. The system requires very precise management of energy input so that fractions are faithfully collected at 25 ml / 15 minute increments. The more faithfully collected, the better we are able to make meaningful comparisons across distilling runs. To maintain a constant rate of flow, the energy required is dynamic and ramps upwards because of how alcohol is exhausted over the course of the run.

Lets just say this ramp is theoretical. The first three fractions are collected at roughly the same energy level because the ABV for those fractions is near the azeotrope. The most significant ramping is in the 4th fraction where ethanol is rapidly being depleted. The 5th-8th fractions are nearly aqueous and collected at roughly the same energy level. Typically when I collect the 4th fraction I use three different ramps and we’ll get to that.

To back up a bit, I advocate using a 500 ml Glas-Col brand mantle (model 100B TM106) over a Chinese version. They do have lead times if you buy directly from Glas-col, but they are worth it. You can often buy them elsewhere with no lead time and sometimes for cheaper. Do not use a Glas-col heating controller because you’ll need something far more precise with a digital read out.

For heating controllers, I own a lot of options and have systematically tried everything, but now I wholeheartedly endorse Auber controllers and have a custom specified version for the birectifier I can direct anyone to (roughly $400). Auber sells what are basically affordable Chinese clones of American Watlow controllers. Auber’s customer service is awesome and Watlow prices will make you cry.

The affordable heating controller option is a Variac (worth watching because some units lack quality) variable voltage controller (make sure it is rated for enough amps) and there are extremely affordable Chinese clones on Amazon. Some have integrated digital read outs for voltage which is ideal, but if yours does not you can install a “kill-a-watt” meter inline to give a digital voltage reading.

[When you go from a modern digital voltage regulator to a Variac, you may notice I’ve made some oversimplifications. I typically count my energy input in volts or a percentage of line current, roughly 40-70. I do this because the numbers are simple to remember and it is highly repeatable. A Variac can also operate this way, but when we compare different Variacs and different mantles and different incoming line currents, we may want to talk in watts. Watts = volts * amps. Instead of “70” as an upward bound for collecting the aqueous fractions, I needed about 250 watts. On my particular Variac that was 113 volts and 2.2 amps. I need to revisit framing the lower bound for the first fractions (it is looking like 125 watts). If you’re trying to understand the numbers on the kill-a-watt, amps will change proportionally to volts. On my particular mantle, the watts are 270 when the volts are 115 implying the amps would be 2.35. Lowering voltage below 115 correspondingly lowers amps and thus has a two fold impact on changing watts.

Some other mantles are 250 watts at 110 volts and thus 2.27 amps. This change would impact the values needed for a heating routine.

My incoming line current is 123 volts. 70% of 123 is 86.1 volts. That means my digital voltage regulator needs 86 volts to do the same work that my Variac does at 113. Because we are evaporating water, we are likely talking the same wattage. The difference then is the devices drawing different amps, but I cannot say why.

This is just something to consider when developing your own heating schedule for your own proprietary heating controller & mantle. You will get repeatable results but your numbers may differ from mine.

Something else to note is that I can install a kill-a-watt easily on my Variac to see volts, amps, and watts, but I cannot put the same device on my digital controller.]

The Glas-col 100B TM106 heating mantle outputs 270 watts which puts the Amp draw well below 10 and gives a lot of options for high end second hand Variacs from eBay (watts = volts * amps).

Make sure your birectifier column is setup plumb (not tilted!) and that the condenser is roughly at a 45° angle, inline, and not twisted. The condenser uses a ball/socket connector to limit potential for breakage, but if the angle is too extreme, the nature of the mechanism will be to reduce the aperture of the bore and create reflux you do not intend or want. If you arrive at one set of heating numbers and they are very different another usage, it could be because your condenser is not at the correct angle and the slight difference varies energy needed by a percentage point or more.

It is safe to call the birectifier initial heat up frustrating (because you want to go fast!). You cannot apply a lot of energy to heat quickly then turn it down. The heating mantle simply has too much inertia. If your first fraction is optimally collected at 39-41% power then that is how much energy initial heating should require and it simply takes as long as it takes. Botching the first fraction is a pain in the ass. Sometimes initial heat up for a 250 ml sample takes 20 minutes. I can reliably set my initial energy for heat up and collecting the first fraction then set a timer and walk away. Most often I can return with only 60 seconds of extra time needed before the first fraction starts being collected.

For fractions 1-8 my current heating profile looks like this:

Fraction 1: 39%  <–Near azeotrope
Fraction 2: 39%  <–Near azeotrope
Fraction 3: 40%  <–Near azeotrope
Fraction 4: 42-55-70%  <–Near azeotrope but alcohol exhausting
Fraction 5: 70%  <–Alcohol exhausted in the beginning
Fraction 6: 70%  <–Aqueous
Fraction 7: 70%  <–Aqueous
Fraction 8: 70%  <–Aqueous

These numbers will differ slightly if you are talking volts directly or reading a percentage of your incoming line current which can deviate slightly from 115V and even vary by time of day.

The first three fractions are very similar in energy required and so are the last three. The fraction that changes dramatically is fraction 4 because near all alcohol is exhausted in that fraction. On your very first running, you have multiple tries to arrive at the correct number for the first three fractions and then again for the last four. On your next running, because you’ve established your beginning energy needs and ending, the focus will be about perfectly executing fraction 4 which may need the voltage changed multiple times. I often change it at the very beginning as the vapor temperature starts to rise. Changing it again after the first 1/3 and then again 2/3 in. To get good results, it is definitely not necessary to sit there and increase the energy by one point every minute.

The biggest problem you can have with the birectifier is not correctly scaling your charge for 100 ml of absolute alcohol (i.e. 250 ml @ 40%ABV). Being under is more of an issue than being slightly over and most of the time taking a labeled ABV at face value or not making a temperature correction for a reading are the source of the error. If too little absolute alcohol is inputted, the 5th fraction (high value aroma) can start early and bleed into the 4th (fusel oil). We are often talking 1.0 ml of absolute alcohol in err. All is not lost; based on rapidly ascending temperature of the dephlegmator thermometer, obvious emergence of high value aroma, and the visual queue of globby water vapor (as opposed to ethanol vapor) in the column, you can simply change early to collecting the 5th fraction. Often you are only forgoing possibly the last 2.0 ml of collection from the 4th fraction. This situation can technically skew your results, but not be overly significant to your interpretation of the fractions.

Energy numbers for collecting fractions have stayed fairly consistent in my lab as spring weather rolled into summer and humidity increased. After a while, I have been able to look at the drips almost like a metronome to know things are proceeding correctly. As a rule of thumb, it is better to be too slow than too fast. As another rule of thumb, for the first four alcoholic fractions, you should be able to count off nearly one drip per second so you can set your stop watch and count out thirty drops in roughly thirty seconds. For the last four fractions, where alcohol is exhausted, the drips change in size and even become less consistent in interval.

Something to restate and keep in mind is that the number percentage is a fraction of the voltage which we only assume is 115V, but isn’t always. A change of a single percentage point can add or subtract an entire minute off a fraction. Heating is that sensitive!

For every fraction I collect as I create my heating schedule, I note the time and update my ramped voltage charts. The more systematic you become, the less time you’ll burn creating your routine. Being very patient with the very first start up will save you a lot of time down the road. It may also be useful to collect your very first run in a 25 ml graduated volumetric cylinder. That way at 5 minute intervals you will know if you are on track (roughly 8ml / five minutes). You can even take a sharpy to your volumetric flasks and divide them into thirds. It is useful to write your energy levels directly on your heating controller so anyone the task is delegated to can start accurately without having to reinvent the wheel.

Initial heating can take almost 15 minutes before a rapid boil even begins. In the next approx 5 minutes before output is collected you can watch vapor slowly start to creep up the walls of the column like a lurchy phantom (it is very cool). The slow pace of this process may also help the vapour come to equilibrium.

If it looks like I am coming up slow, two or three minutes before a fraction is due, I increase the energy by a point. Fifteen minutes is an ideal, but do not panic if you are collecting a few fractions at 16 or 17 minutes.

Arroyo likely had an army of interns fidgeting with Bunsen burners and counting off on pocket watches while smoking cigarettes (The first four fraction by pocket watch, the last four by cigarette intervals).

To first prepare my sample, I find the ABV. If the sample is 40% then 250 ml are required. The formula to use is 10,000 / ABV so if the sample is 45% ABV then it is 10000/45=222.22ml. This sample would then need to be watered to a minimum of 250ml (I use a 250ml volumetric flask). Notice the formula simply has the numerator and denominator multiplied by 100 to avoid decimals. You could also simply use 100/.40=250ml. It is always a good idea to add 10 ml of water to rinse the volumetric flask so that no absolute alcohol is missed.

The math adds up to there being roughly 50 ml of aqueous stillage (which it is beneficial to analyze just like a fraction), but what would happen if we wanted to analyze something like Chartreuse or Cointreau that have sugar? As a rough estimate, the sugar in a 250ml volume of Cointreau occupies 32ml. If all eight fractions were collected, the stillage would be as thick as molasses! The solution to analyzing liqueurs may simply be to not collect the last fraction or possibly even the last two. There is likely enough information in fraction 6 that the last two are redundant and this advice has conformed to numerous case studies.

This brings me to another point. When you understand your fractions and how they correlate to your production, you may not need to collect all the fractions. With gin, we have found the last two fractions contain no usable information that isn’t already in fraction 6. Not collecting the last two can save a half hour. The same can be said for extremely routine work with distillates you know well. If your objective is only to assess decisions related to your heads cut, you may not benefit from collecting more fractions than you need to make a decision. However, do not run with this concept too far until you are very experienced. The last three fractions would contain any potential fermentation faults so doing a check up is always a good idea if you have the time. You may also discover variance in fraction 5.

Years ago, when I started running the birectifier I relied on supplying the condenser with coolant by directly connecting a hose to a faucet. However now, my setup is in a room with no water supply or drain. I simply use a 2 gallon bucket and a peristaltic pump. The birectifier is considered micro distillation which is why the dephlegmator can be air cooled successfully. My 2 gallon reservoir for coolant is never even warm at the end of the process. This portability means the unit could even be mounted securely on a cart (clamped down!) with an extension cord to help any kind of multi tasking. However, operation is predictable and it isn’t impractical to set timers and simply walk across a room to change a flask.

With experience, and no specific background in wet chemistry, I have been able to run the birectifier accurately and minimize active time with the unit so that I can multi task during the process. Frequently, once a fraction starts, I set a timer for 14 minutes and only come back to observe the last 60 seconds.

I would appreciate any feedback that could make this clearer or more concise.