StillSmart

Hi everyone,

I've been using the airstill for a year now and had no problems until last week. I'd stripped a tpw wash and was doing the spirit run with the low wines, and it burped. Multiple times. Not so badly that it was catastrophic but it was concerning nonetheless.

My experience has been that stripping runs can burp. I've had a couple where the lid wobbled but stayed on. But never have I experienced it doing the spirit run. This time it burped to such a degree that the lid lifted on one side and some liquid trickled down the side, and highly alcoholic vapour was released.

I usually water down my low wines to 30% and use copper pieces in the still, more for its other properties rather than to break up the boil. I do not make cuts on the stripping run, preferring instead to make them on the second distillation, so everything from the strip gets thrown in. No issues with doing it this way before.

On the third time I turned the still off, let it cool and added anti foam. No more burping. It seemed to be ok further into the distillation anyway, apparently only burping early on when the heads started coming out.

My question is, what could have caused this? Abv was low, the low wines are crystal clear and there were boil enhancers in it. Still was filled to the 4 litre mark and no higher. Is it possible my still is suddenly drawing too much amperage and heating too quickly? I checked the lid for blockages on the output and it's clear. Took the o ring off and cleaned it (was a bit gunky underneath), so thinking that might have been it.

The only thing different about this run was the tpw took ages to ferment. Like six weeks. Cooler temperatures seemed to slow it to a crawl, so I used a heat band to get it going again in the last week. I don't see how that could affect it.

Any ideas?

IMO and this will start a fight.

You need COPPER coinage - not just copper rings. They do no do the same thing.

Age old topic - mucho reading on this fourm. Try searching 'coinage'

Hmm interesting..

I personally agree with Mash that Cu coinage is a good thing - they lie flat on the bottom of the still and then bounce slightly as the run gets going, preventing superheated bubbles from forming. BUT, there's enough folk around here who disagree with him and don't use coinage, so who knows?!

As you say, on a spirit run it's a bit odd. Let's think about what could push the top off an AirStill..

Over-frothing of a wash - unlikely in this case - low wines aren't (generally!) fizzy.

Superheating - we've all seen the video of putting a teaspoon in a cup of water heated in a microwave, I guess? It could be, but what's your trigger? A clear wash should heat cleanly in my view.

A blocked output - that would do it, as the still would tend to pressurize a bit, pushing the lid off.

A damaged/dirty seal - would provide an alternative exit from the still and given what happens with a kettle when you leave the lid off, might well be your problem. You can get replacement seals, though I can't remember the site I've seen them on.

Heating up too quickly - I guess that would do it, though I'm struggling to think how an AirStill would fail and heat up faster than it should.. Did the run take any less time than you would expect?

I think that's the obvious ones, with my tuppence-worth - anyone want to add anything?

Cheers

Hampk

Superheating will occur in strip and spirit washes. It's a 'feature' of heating a liquid that is stationary.

Mash wrote:Superheating will occur in strip and spirit washes. It's a 'feature' of heating a liquid that is stationary.

Fair comment. However the copper pieces in the tub should have provided nucleation sites, so I'd still be surprised if it was superheating..

I guess the strangest thing is that I ran this exactly as I've done the last 8 tpw runs and this is the only one that burped.

Noted about the coinage, and I might have some old coins around I can try.

The seal was my first suspect but I can hear the light bubbling sound stop for a few seconds before one large bubble occurs and the lid either pushes up or off, so I think even with a new seal the pressure would lift the lid.

This run didn't seem to be any quicker than normal but I never time them anyway. I sit next to it and collect in jars, and however long it takes is how long I'm there. Never thought to time it for that reason.

I'm going to try water in it on the weekend and see if it does the same with the copper pieces. If it does it with water I'm going to put it down to the pieces not doing enough. Why it has only just started burping I do not know but nothing else seems likely at this point. I will thoroughly clean the copper too.

I appreciate everyone's input.

I am afraid to say that I have no advice to offer, based upon experience.
I will be the first to Poo Poo the coinage theory, as in 5 years of running the smart still,I have never used them, never needed them, Copper off cuts work fine for me.
I once had a boil over during a strip, never a spirit run.
I really do not have an opinion as to what you experienced.
But I am not trying to defend anything.
Sorry that I cannot help you this time.

Robert.

hampk wrote:
Fair comment. However the copper pieces in the tub should have provided nucleation sites, so I'd still be surprised if it was superheating..

It's not necessarily nucleation sites. The flat coins vibrate, flip and jiffle creating movement thus thwarting superheating.

Copper off cuts of any shape just sit there,wobble a bit and don't Whistle Dixie?
Come and listen to my stills sometime.

IMHO any and all bits of copper work for anti boil over and sulphur/sulphite take up, and cleaner spirit.


They also seem to do the anti surge thing pretty well.

Robert.

I'm thinking about throwing a few more pieces of copper in, regardless of shape. Just whatever I can find. Coins won't be easy because they haven't been circulation here for a long time. I figure by the way the surge sounded that literally any physical object would help prevent one big bubble, and I suspect I just don't have enough in there. Not sure why it's never been a problem before.

Next sugar wash isn't even fermenting yet so I've got some time to run water tests and see what happens.

I use about 1/2 a tumbler of copper to get a good cover.

I use a dozen or so copper coins and don't use conditioner, but my winemaking background means I'm pretty obsessive about de-gassing.

That said, can't see it being relevant to spirit run.

You can buy copper coins quite reasonably on the auction site, but I'd consider a replacement seal/gasket. UK airstill suppliers such as love brewing sell them but they are a silly price http://www.lovebrewing.co.uk/sealing-ring-for-air-still/

Curmudgeon wrote:I use a dozen or so copper coins and don't use conditioner, but my winemaking background means I'm pretty obsessive about de-gassing.

That said, can't see it being relevant to spirit run.

You can buy copper coins quite reasonably on the auction site, but I'd consider a replacement seal/gasket. UK airstill suppliers such as love brewing sell them but they are a silly price http://www.lovebrewing.co.uk/sealing-ring-for-air-still/

Got two today... £3.50 postage

I think £8.90 a bit steep, but that's fair for postage.

I do get the coinage or whatever going quiet, but never the lid lifting, which is why I'd replace the ring.

Sometimes I have to get swmbo to hold the still with one oven glove while I wrestle the lid with another. No way mine would lift on it's own without a major problem.

edit : a bungee cord hooked under both sides and holding the lid down woulddn't interfere with airflow much

I would have a new seal. Mine doesn't come apart easily.