Stopping Your SmartStill Superheating
Jimmy | April 1, 2008
After our recent article about preventing the top popping loose on your SmartStill/EasyStill, I’ve received some more detailed information about the issue. It seems that all stills now come with a set of Raschig rings, as I recommended earlier. If you have one of the older models, then my advice to purchase some for yourself is still valid.
Superheating is when a liquid is heated to higher than the normal boiling temperature, without actually boiling. This can typically occur when the heating takes place in a very smooth vessel, such as a laboratory glass jar or similar. In this state, the liquid is metastable - i.e. it will not boil as long as nothing disturbs it. However, if you add any object or cause the liquid to move, it is likely to break the metastable state and start to boil which will then happen violently.
An example of this would be when someone heats a cup of water in a microwave oven (one without a rotating dish). It sometimes “explodes” in violent outbursts of boiling when you take it out, when you put in a spoon to stir it, or when you add a lump of sugar.
The reason that this sometimes happens with the SmartStill is that some of them are smoother inside than others, due to the manufacturing tolerances. The smoothest ones can sometimes have this issue, for the reasons outlined above. When the first bubbles form, the liquid is above its normal boiling point and there will be an explosive outburst of boiling as the bubbles break the metastable state. This can also happen if you move the SmartStill at this stage, or even worse (NEVER DO THIS!), remove the lid to see if it is boiling.
The solution is simple - add something non-smooth, to prevent superheating taking place.
The perfect thing to add would be inert, easy to clean, and heavy so that it stays at the bottom. A good example would be “SmartRings” which are simply Raschig rings, as used in distillation columns. Simply add them to the SmartStill before you start distilling and the problem will most likely go away. They are now included with each still, but were not there originally when the problem wasn’t apparent. They can be re-used forever, just rinse them between distilling runs.
WARNING!
NEVER add these rings to an already heated liquid. If you do, you could trigger boiling which could make boiling liquid explode out of the still, most likely onto your face and hands.
ALWAYS add them at the start, then add liquid, close the still and distill as usual. Don’t open the still until it has completely cooled down, as per the manufacturers instructions.
As long as you follow these simple guidelines, you will have no problems with your SmartStill - happy distilling!
This "over boiling", apparently, can also occur if your wash/mash
Fatbloke | June 1, 2008This “over boiling”, apparently, can also occur if your wash/mash isn’t as clear as absolutely possible.
It seems that it’s to do with the surface tension of the bubbles that are produced by the boiling process i.e. normally, individual bubbles will rise to the top of the liquid in the still, bursting individually.
Now I don’t recall if it’s a reduction or increase of surface tension, but the bubbles can join up, and when they rise up to the top of the heated liquid surface, they obviously burst, but that can sometimes cause enough of a pressure build up to lift the lid and “burp” the still.
I’ve had this twice, on the first occassion I’d distilled a “turbo sugar” wash in my reflux still, but because of the presence of either sugar that hadn’t fermented or yeast nutrient that hadn’t been eaten up by the yeast, the distillate was a little cloudy.
I managed to remove some of this cloudiness by running the distillate through a “Z filter”, but not all. So when it was heating up again, this time in my “smart” still, it got to a point where it “told” my partner that it wasn’t happy with a little burp, I went to the kitchen and as I leaned across to cut the power it burped again, except this time it showered me and the kitchen in about 3 litres of 85% alcohol.
Luckily, hot alcohol cools very rapidly i.e. a small amount flung from a cup will be cool in the distance of a couple of metres. The net result of this was that I experienced a “sunburn scald” across my arm and down the side of my chest. Just red skin and a little soreness (and the added bonus that alcohol of that purity is one hell of a good cleaning liquid).
On the second occasion, knowing that it normally takes about an hour and a half to heat to the point, where I see some distillate condensing out of the still, I was “running” 4 litres of cider (hard cider for those in the US), but it didn’t like the fact that the cider had only partially cleared (naturally) at the end of the ferment. That didn’t hit me, it just blew the top off the still and showered the kitchen - which stank of cider for about 3 days after.
I’ve since found out that one of the ways of curing this problem is as per the article (the “cider accident” actually had some broken glass in the bottom of the still to act as the rings/boiling chips).
Also, the inclusion of a substance called “Distillers Conditioner” to the batch before it’s distilled can also (help) prevent this problem - it should be available through your distillation supplies provider.
Thanks for that, all good advice!
Jimmy | June 1, 2008Thanks for that, all good advice!
Hi! I mentioned on the "foaming over" thread that I
Canyon Cat | June 6, 2008Hi! I mentioned on the “foaming over” thread that I had placed a new brass water faucet handle in the bottom of my new EasyStill. Despite the unclear Tubo 48 wash I put into the still, I got a very quiet and steady run with no surprises.
As I surmised before, I think the modifications made to the EasyStill have alleviated this overheating problem.
Call me a sap for spending $265 USD on the EasyStill but I’m very happy with it (so far). I got exactly what I wanted: cheap ($1.60 USD/750ml) and drinkable ethanol from a discreet tabletop appliance. I see a ROI (Return On Investment) within the year. Color me contented, Mates!