DIY false bottom for Burco

[The-Engineer-That-Brews]

Does this stuff not have to be 304 grade SS or whatever to prevent metallic tastes?

Maybe... haven’t ever had any problems with that though. Tbe honest, while I’m aware there are different grades of stainless steel I just tend to treat them all as one. For sure it’s better than mixing different metals like stainless, brass and copper together in electrical contact with each other... that‘s certainly something to be avoided in the presence of an acidic wort.

 

[Ashman]

Did it work better with the larger holes?
Wilko’s had a 28cm (at the rim) stainless mixing bowl. Although I need 29cm and something shallower it was only £3. I assume I can punch holes in it as the stainless seems thin. Whether it works.... I’m thinking a dog bowl might have been better?

 

[The-Engineer-That-Brews]

Did it work better with the larger holes?

Much better, thanks. In testing I found 3mm holes spaced about an inch apart were needed in order to let the bubbles through fast enough during a full boil... with the 2mm ones the bubbles were still pooling together and impeding the circulation leading to occasional blow outs.

Wilko’s had a 28cm (at the rim) stainless mixing bowl. Although I need 29cm and something shallower it was only £3.

Nice one at that price you can’t go far wrong eh? Don’t worry about it being a bit deep: you just fit a dip tube through it, that reaches down to just above the floor of your boiler. Link that to your tap using a bit of silicone hose and you’ll be able to siphon out right down to the last few millilitres. You could do it by drilling a hole and putting a grommet in, then pushing a bit of pipe thru. ... or you could just epoxy a bit of pipe in to the hole maybe. Just make sure you don’t have different types of metal in electrical contact with each other or you’ll get corrosion and metallic flavours.

You‘ll need some way to make sure the bowl stays held down a bit, otherwise during the boil it will get buffeted around and hop debris will get under it. You could use my approach of jamming a bit of silicone hose down the side, but you might find that with the sloping sides of the bowl it might pop out. Another option is to use high temp rare earth magnets to hold it down - make sure you get the Samarium Cobalt ones though (available on eBay) otherwise they will quickly (and permanently) stop working at 100°C. Another option might just be to put a weight on it to hold it down - perhaps a couple of glass paperweights?

You‘ll find that stainless is quite tough to drill and it blunts bits pretty fast. It’d be worth getting a few spare bits cheap off a market stall. Also watch out for the burrs because they can be razor sharp!

Good luck and please share your results!

 

[Scrattajack]

Maybe... haven’t ever had any problems with that though.

Nice one, I'll get my order in then. Many thanks, been struggling to find a decent false bottom that wouldn't lead to bankruptcy.

 

[Scrattajack]

You‘ll find that stainless is quite tough to drill and it blunts bits pretty fast.

I read recently that stainless steel becomes harder the hotter it gets, so a slow drill speed is the way to go.

 

[Gerryjo]

Does this stuff not have to be 304 grade SS or whatever to prevent metallic tastes?

Just to make you aware that 304 SS does actually rust and can cause metallic flavours if not treated correctly.
Preferrably 316 but that's real expensive.

 

[Scrattajack]

Just to make you aware that 304 SS does actually rust and can cause metallic flavours if not treated correctly.
Preferrably 316 but that's real expensive.

Bugger. Well, there hasn't been any rust/metallic taste so far on my 304 stuff, what do I have to do to keep it that way beyond cleaning and drying it off after use?

 

[foxy]

Bugger. Well, there hasn't been any rust/metallic taste so far on my 304 stuff, what do I have to do to keep it that way beyond cleaning and drying it off after use?

304 is fine if it hasn't come into contact with a file, grinder or hacksaw which has been used on ferrous metals.
I would like to know if those using false bottoms are getting a good vigorous boil? Could be eliminating one problem and creating another.

 

[Gerryjo]

Bugger. Well, there hasn't been any rust/metallic taste so far on my 304 stuff, what do I have to do to keep it that way beyond cleaning and drying it off after use?

Nothing just keep up what your doing by washing after use and drying and it will keep.

 

[The-Engineer-That-Brews]

Nothing just keep up what your doing by washing after use and drying and it will keep.

And don't put it touching other types of metal that are also in contact with the wort ((esp. copper or aluminium). That creates a battery and is guaranteed to give you galvanic corrosion.

Certain types of brass and stainless can be interworked in the same system, but they need to be very specific types.

If you want to know more, try this: https://www.worldstainless.org/Files/issf/non-image-files/PDF/Euro_Inox/Contact_with_Other_EN.pdf

 

[The-Engineer-That-Brews]

I would like to know if those using false bottoms are getting a good vigorous boil?

Yep - I tested the 30cm 'modified' version with the 3mm holes at full boil yesterday on a 25L batch and there were no problems at all:

• the bubbles from the boil were steady, vigorous and distributed evenly across the full diameter of the kettle
• there was no 'bumping' due to water being 'trapped' under the mesh and getting superheated
• the sieve itself remained firmly in contact with the base of the boiler (checked for movement by pushing down with a long paddle all the way round the edge)

Just for clarity that was using the 20mesh (0.9mm aperture) with the holes opened out to 3mm every inch or so using a tapered spike.

I'll add that when I cut the 'bite' out of the side to accommodate the Burco's tap entry, I made it just deep enough to fit. This ensures that the sieve is held down tightly on that side. The short section of hose jammed in the gap on the side opposite then worked well to keep the whole thing firmly in place.

 

[CD]

The false bottom I made from a circular piece of stainless steel sheet for my mash tun has holes of 1.8mm diameter, and as I have never had a set mash that seems to be about right.

 

[Andy_K]

Helix (stainless steel extension spring)
View attachment 35370
All hops and break material left in the kettle.

Hi Foxy

I’m interested in this solution but a bit confused.

Without the spring being extended, how does the wort get through it?

Can you provide a link to the type of spring you’ve got?

Is the end that is not connected to the outlet tap blanked off?

 

[The-Engineer-That-Brews]

The false bottom I made from a circular piece of stainless steel sheet for my mash tun has holes of 1.8mm diameter, and as I have never had a set mash that seems to be about right.

View attachment 35606

That's a nice bit of work @Coffin Dodger :-) However the requirements for a kettle screen are a bit different versus the false bottom for a mash tun. It's got to let vapour bubbles come upwards from the element at a pretty high rate, as opposed to wort coming fairly slowly downwards with a fair bit of pressure behind it :-)
Also the surface tension works very differently for bubbles of air coming upwards, versus liquid coming downwards: until I saw it wiv' me own eyes I wouldn't have believed that quite large air bubbles would just 'pool' under 2mm mesh rather than bubbling through it! That creates a serious problem in the base of a boiler, because it creates a barrier that stops the hot wort next to the element from circulating properly, leading to it overheating and making a sudden 'geyser-like' eruption in the boiler (not something you want to happen.

 

[The-Engineer-That-Brews]

Hi Foxy

I’m interested in this solution but a bit confused.

Without the spring being extended, how does the wort get through it?

Can you provide a link to the type of spring you’ve got?

Is the end that is not connected to the outlet tap blanked off?

I'm guessing that the 'bend' on the outside of the spring as it coils round inside the circumference of the boiler opens it out just slightly on that side, making nice little 'slits' that the hop debris can't easily pass through :-)

I imagine it's like this one: Helix Coil Kettle Tube | MoreBeer

 

[foxy]

Hi Foxy

I’m interested in this solution but a bit confused.

Without the spring being extended, how does the wort get through it?

Can you provide a link to the type of spring you’ve got?

Is the end that is not connected to the outlet tap blanked off?

It depends on the diameter of the wire making the coil, I got mine made using 2 mm wire 20mm o/d. These still work in large diameter kettles, I did try a short straight piece in a fermenter with water, just dribbled out. With cool wort it works better @ 2 meter length, bigger surface area. Because it coils the spring opens slightly (why the wire dia is important) the opening of the coil is barely visible.
The end of the tube is blanked off with a copper capillary fitting, while copper is OK, even beneficial in the kettle, it isn't in the fermenter.

 

[CD]

That's a nice bit of work @Coffin Dodger :-) However the requirements for a kettle screen are a bit different versus the false bottom for a mash tun. It's got to let vapour bubbles come upwards from the element at a pretty high rate, as opposed to wort coming fairly slowly downwards with a fair bit of pressure behind it :-)
Also the surface tension works very differently for bubbles of air coming upwards, versus liquid coming downwards: until I saw it wiv' me own eyes I wouldn't have believed that quite large air bubbles would just 'pool' under 2mm mesh rather than bubbling through it! That creates a serious problem in the base of a boiler, because it creates a barrier that stops the hot wort next to the element from circulating properly, leading to it overheating and making a sudden 'geyser-like' eruption in the boiler (not something you want to happen.

Sorry, I thought it was mash tuns, not coppers (kettles?) being discussed.

 

[phillc]

Helix (stainless steel extension spring)
View attachment 35370

How difficult (or easy) is the cleaning of such a coil?

 

[foxy]

How difficult (or easy) is the cleaning of such a coil?

Real easy, hook the end over something give it a stretch and then hose it down.

 

[The Furnace Green Brewer]

I thought I'd share how I made a new false bottom for my Burco (30L Burco Cygnet MFCT1030 to be precise) to strain the wort from the hops after the boil.
In the past I've used a mesh filter fitted to the inside of the tap, a bit like a 'bazooka' style one, but I got a bit fed up with (a) the amount of wort it leaves in the boiler; and (b) the inconvenience of cleaning it out.

Here's a pic of what I made, and of it installed in the boiler:
View attachment 35314 View attachment 35313 View attachment 35318 View attachment 35316

So basically it's just a 30cm one-piece stainless steel tamis (drum) sieve, with a skin fitting ('SKF') marine tank drain fitted through the middle. I clipped out a neat hole for it with wire cutters.

You can see I also cut a bit out of the side to make room for the tap, but other than that the only tweak was to put three small (M2 x 8mm) stainless bolts through to stop the weight of wet hops pushing the drain down against the floor of the boiler.

The 30cm diameter fits nice and snugly into the 'outer' tapered recess in the floor of the boiler and the drain fitting sits nicely above the inner recess in the centre. The bend on the silicone hose pushes it towards the back though so I stuck a little offcut of hose in there to keep it centred (top left of first photo).

The only thing I'd change another time would be to use a coarser mesh sieve. This one is 20 mesh (0.9mm hole) but 10 mesh (2mm hole) would be better because the 20mesh stuff traps bubbles of steam under which makes boiling a bit too 'bumpy'. That's easily fixed by putting a few 2mm holes through here and there.

Just for reference, the parts I used were:

• 30cm 1 Piece Stainless Steel Sieve: I used this one from Amazon (£16.67) but I suspect this one from eBay (£5.84) would be the same if you don't mind waiting for delivery
• Stainless Steel Skin Fitting 15mm 16mm Hose Boat Marine Bulkhead Drain: this one from eBay (£9.39)
• 1/2m of 13mm inner diameter silicone hose
• three 8mm small (e.g. M2) stainless nuts and bolts