Wort chilling help required

[Karl Hayes]

Hi folks.

I wonder if anyone had any experience on cooling 80L of wort, quickly. I have access to medium sized 7,500BTU to 12,500BTU) AC units and the ideas I'm kicking around my head are

• to replace the AC condenser system with a copper tube, closed loop immersion chiller coil, or
• to use the original condenser to chill a large container of glycol or brine and pump that through an immersion chiller, or
• fill a chest freezer with about 250L of brine and reduce the temps slowly over a few days, then use this as a sort of reservoir for pumping through an immersion chiller on brew day

I'd prefer not to go down the plate chiller path. Any thoughts anyone?

Cheers.

[Peter Smith]

Why not a plate chillor, its a lot easier to sterilise and way easier to move around etc, also it does not effect the boil at all.    http://www.northernbrewer.com/shop/therminator.html       nothing to fail except mains water....    

I have a immersion chillor for simplicity but it takes a long while on a 40L brew (think 60 mins) and its needs cleaning as the hops cake on during the boil.  As I build a bigger system I will def go plate.

[Hamish Jones]

I use a plate chiller and though they work really well, man do they get clogged up with some crap you've got to keep on top of them and even after a few brews when you think you've been fastidious with cleaning they still get build up on them

[mattd2]

How are you cleaning your chiller out. I was flushing / back flushing a few times after brew day. But it has been a while since I had brewed and on Saturday so I did a flush / back flush before setting up and a whole lot more crap came out. After brewing I did a Oxymagic (sodium percarbonate) clean at 50°C for 1 hour and back flush a couple of times then rinsed. Hopefully this got all the nasty gunk out but I agree with you that they are potentially a trap for all sorts of nastyness if your not thorough!

[Hamish Jones]

I flush and back flush with the hose straight after brew, then I circulate dish washer cleaner through my whole system at about 75 degrees for about 30 minutes then back flush for another 30 minutes, after that I leave to soak overnight, about every three brews I leave it circulating for a couple of hours

I made the mistake of soaking my chillout plate in sodium percarbonate over night and the welds to attach the studs on the back weren't stainless and they rusted, I was thinking about using caustic but they are braised with copper and from what I have read copper and caustic aren't good together so I am going to get some PBW to clean my system and see if that's more efficient

[Karl Hayes]

Hi Peter

I'm not too keen on plate chillers.  do sell them from my shop but they're only suitable if sized correctly.

Too much risk of infection because a) they're impossible to clean properly unless you spend thousands on one that can be dismantled and b) there's too much hot wort producing nasties as the 85L trickles slowly past the chiller.

Cheers.

[Grant R Baker]

I'm not sure about using an AC unit too close to wort... too many bugs in AC systems... but if you are able to use it safely then maybe a counterflow cooler with the glycol idea would suit.

I'm not talking from experience here.. My biggest brew to dates was 40l.

[Karl Hayes]

Thanks Grant. I have a brand new AC unit that I bought to make a chill room which my landlord has vetoed, but I think the solder would dissolve in acidic wort so the condenser is going nowhere near the wort in any case.

[Richard Jack]

Why not just use a bigger immersion chiller? Multiple coils plumbed in parallel. 

[mattd2]

Looking through the options you listed, consider that 7500 - 12500 BTU/hr equals 2.2 - 3.7 kW which is probably (a lot) less than the heat power you are using to get it to boil.

For option 1 it would theoretically take (calculating just for the thermal mass of the wort not any heat stored in the equipment, etc.) 2 to 3.4 hours to chill 80 litres of wort from 100°C to 20°C.

Option 2 & 3 are kind of the same just a different amount of DIY and the chest freezer option you are relying purely on the "stored" heat capacity of the 250 litres of brine. But using brine would give you head aches with corrosion issues in any copper/stainless as it would be a mission to get it all cleared out between brews and probably waste just as much water to do so, maybe use glycol and store it - but that means a dedicated freezer for glycol though! If my thoughts are correct 250 litres of -4°C brine/glycol and 80 litres of 100°C wort would equal out at about 21°C, but getting the last 10(ish) degrees might take its sweet time.

If all you want is getting the wort down to pitching as quick as possible nothing will beat whatever type of chiller you decide on run with water at full bore and if using a plate/counterflow chiller restricting your wort flow so you are at pitching temp after one pass as you will be chilling only the wort that way not the kettle, etc as well. If using a IC then make sure the wort is being "stirred" either by recircing or by hand to make sure you get hot wort flowing over the coil all the time.

Paul / another1 did a YouTube video a while back comparing between one pass and recircing and found the the time difference wasn't hugely significant and I think the final recomendation was to actually recirc till you hit a temperature where you can run the wort full bore through the chiller and hit pitching temp on the way out.

There is also prechilling your cooling water with another imersion chiller in a bucket of ice water.

If you are worried about water wastage there is stuff you can do to minimise water usage but from what I have seen most people who have tried to go down that track for homebrewing eventually end up at the point that reusing the hot waste water is more practical than trying to reduce it - water the garden, fill the washing machine (if you can), take a bath in it!

Hopefully that wasn't too over the top!

For me (just 15 - 20 litre batches though) I use a plate chiller and recirc back into the kettle. I reduce the chilling water to a point where it is coming out of the chiller at roughly as hot as the wort going in. Once the wort is down to about 30°C I open up the chilling water and wort goes straight into the fermenter which usually gets my wort down to about just under 20°C with tap water at about 15-18°C.

[Karl Hayes]

Thanks for this Matt, lots of ideas here. I think I will go with a large immersion chiller and test it with boiling water before using it in Production. If I still need a bit of a kick towards the end of the chill (especially with warmer ground water in Summer) I will pipe the water through a chilled glycol bath.

I've uploaded a pic of the proposed 120L Kettle with a 20MT copper coil.

[paul m]

Hi Karl, biggest boil i've done is 35L. Not 80L, but  I'm in the winterless north and on tank supplied water. So my water supply can get pretty warm in the summer. I use 15m of 12mm copper pipe immersion chiller. I made two chiller one 5m other 10m. The 5m chiller i put in a bucket with water and slickerpads and ice and use that as a prechiller before the chiller in the wort. I reckon the pre chilling speeds things up big time. I think that stirring the wort to get as much of it in contact with the chiller make a significant difference. Use a recirclating pump or stir every 5 minutes to keep it wirlpooling. hope that useful, cheers Paul

[G S]

My 2 cents worth, maybe over simplifying ?, .
There's really only 3 variables you can play with to get a better chiller:

1 surface area. More pipe, or increase length, decrease diameter, or get a monty big hx. A coil within a coil, or staggering the coils L &R must help.
2 temperature difference. 20 deg c tap water sucks plenty heat of 80 c wort, when the difference is only 2c, then not much. If you have access to a chiller, or slicker pads and a 2 stage chiller, etc , then i think it's best used at the end, once the worst down to 25 or so. Perhaps use tank water at first, then run chilled water through by gravity towards the end. If you have a counter flow chiller, then yes, use chilled water from start.
If you can get a thinner pipe it will help as well.
3 velocity. The faster the wort moves past the surface for more heat transfer can happen. a pump whirl pooling going at same time, 'Jamill' chiller I think?, stirring probably does the same.

Counter flow chillers are so effective cos the temp difference is best utilised, the coldest water is used right at the end when it can do most good.