Stainless steam extract

[barneey]

Since I posted my original design, which works very well, still getting approx 10% boil off during the process + havent notice any odd off flavours yet. I have been thinking about a mark 2 hybird version after seeing Dellars excellent purpose made cone.

Heres a couple of shetches of the idea, I`m looking for either suggestion or flaws in the design, be as critical as possible:- (couldnt find a fag packet (as I dont smoke) + cant use CAD so a quick pen sketch.)



The pot dims are an 80 ltr thermo boiler pot.



Failing that something like a chicken feeder http://www.ebay.co.uk/itm/30l-Metal-tri ... 3a701ac8cc ie an oversized cone similar to your, supported on 3 legs which then simply sits over the open pot. A channel of some sort then collects the condensation.




Cheers

[Kev888]

I like Deller's design very much too, but I'd doubt that practically speaking your existing setup is notably deficient either, so if it were me I'd want to be convinced that the MKII would be beneficial.

In winter (when steam/condensation is more of an issue) I also use a flat-ish lid and a vent tube and haven't had any problems with steam or DMS getting out adequately - though by retaining the heat above the foam, it does need a closer eye to stop boil-overs. Also, I value the benefits of a well-closing lid, so that you can keep flies out post-boil (and maybe use Clean In Place sprays and so on), so I'd suspect it could be half a dozen of one and six of the other, really.

Cheers
Kev

[Deller12]

Hi Kev,

I normally loose around 5 liters during my boil and even with my cone I still get water droplets falling back into the boil kettle. I have recently have had a couple of bad brews but his is down to infection this I believe is down to poor sanitizing Apart from this problem I have never had any off tastes so am wondering of some falling back into the brew is a major issue. What do the big brewery’s have to stop this problem ?


Lee

[Kev888]

Hi Lee,

Some falling back into the brew is not in itself a problem (provided you account for it in your evaporation loss calculations). The boiling wort will sanitise any returning droplets and the lid or cone will almost certainly be sanitised by the heat and steam by the end of the boil, so post-boil droplets from that aren't going to be an issue either. The only thing I'd suggest is putting an elbow or bend in the vent very soon after the lid/cone, so that anything condensing further along the vent (which may be less hot and less well sanitised) runs away from the boiler, rather than back into it. Of course if you have a cone and a gutter to channel and catch returning droplets instead, thats going to work well too so its a perfectly decent thing to do.

Similarly with DMS - lots of people get over-concerned about this IMHO. Its a lot more volatile than water and so won't condense on the hot lid in the same way, rather it will be driven off along with the steam. This has been proven time and again by people brewing on here with vents/chinmeys rather than uncovered boilers, and most breweries have some sort of vent affair too, and it doesn't result in excess DMS. In fact it can help; the boil can be stronger without so much heat escaping directly out the top, so 'provided theres no particular restriction to stuff escaping' a smaller exit for the steam etc makes things more efficient.

Cheers
kev

[barneey]

With the system I have at the moment condensation does collect on the underside of the lid, no real way of stopping it doing otherwise, the vent itself is the 90 degree bend with only a 1m length of hose to the external elements at a slight angle downwards to prevent any drop back. If I have may calcs right the outlet being 50mm diameter = Pi R2 = 3.14*25*25 = 1962.50mm2 area the internal lid area being 460mm diameter = 3.14*230*230 = 166106mm2 exposed surface for condensation = 166106 - 1962.50 = 164053.5 mm2 or 0.164m2 area. With the cone (without sitting on a channel) would the area exposed to condensation be greater? but or be more efficient at getting the steam away? With the channel idea regardless of areas involved any condensation formed wouldnt in theory re-enter the brew.

Am I just being a little paranoid about the whole thing? Judging bu your post above Kev it seems highly likely.

EDIT just done a few more maths and any cone not being an equilateral triangle / cone will have more surface area than the flat surface area (someone please correct if wrong) thus making a 45 degree angle the lowest surface area, but there must be a trade of with liquid running down the sides ie conical fermenters are at 60 degrees.

Sorry for the ramblings....

[Kev888]

Yes, IMO I think you may be worrying too much. Not that its wrong; the cone shape is perhaps the obvious shape for funelling steam out if you had to make a lid from scratch, but I'd just feel that its unlikely to be noticably superior to your existing (gently domed) lid in practice and I doubt it would reduce condensation (in fact with the larger surface area I'd probably expect the opposite, though perhaps the funelling shape would mean less vapour touched it, not sure).

But either way, condensation of some of the steam doesn't matter (provided your assumptions on evaporation losses account for it) - perhaps if you needed to be rendering down for significantly higher gravity it would speed things up to reduce it, or if you didn't have the elbow so dirty crudd from higher up the vent could return, but otherwise its not going to be a problem.

It would definately matter 'if' DMS condensed and returned in significant quantities too, but it won't do that if the lid is reasonably hot (which it will be). I can't recall exactly what temperature the lid needs to be at to prevent it condensing but its really pretty modest - I seem to think about 40c or so. So it will be carried away with all the escaping steam.

Cheers
kev