Immersion chiller

[Ceejay]

A mighty interesting thread. I wish I could remember all the thermodynamics I studied 10 years ago, but alas the knowledge has leaked out of my ears!

Anyhoo, so is this a valid conclusion then:

For 90% of homebrewers an ideal approach is to use an immersion chiller with a flow rate balanced to achieve an outflow temp slightly lower than that of the wort. Once a good yeast head forms in the FV, it's best to give it a light skim to remove any break material and stop it from re-entering the beer once the head dissipates.

?

 

[Alan Robinson]

Most fridges and chillers are unable to deal with the 'total amount' of heat contained in a batch of wort. The really effective way to chill using a chiller is to cool a batch of liquor down to 4-6C and then pump that through a very efficient plate chiller (Wort going the other way) of course. You can effectively chill 18BBL of wort with 18BBL of cold liquor very quickly (The time it takes the wort to pass through the chiller).

What is important to remember is that to go from 100C to 35-40C is relatively quick (delta T is High) . . . even with an immersion chiller, but as the temperature of the wort gets closer to that of the coolant the chilling effect is lessened (delta T is low). In order to retain effective chilling it is at this point that you need to increase delta T (by chilling the coolant), either by an additional coil in a bath of crushed ice (with a pump to recirculate the ice water), or an additional plate chiller connected to a bar chiller or a chilled pumped reservoir. Of course at the moment where the groundwater temperature is so low. . . chilling should not be that much of a problem

I get your point. Newton's law of cooling. My idea was to put in permanent piping, and then fill the thing with something denser than water, yet with good thermal conductivity. I'd run the fridge for a couple of days before brewing to get the whole caboodle well and truly cooled down.

I knew a guy from Fiji who told me about those lovo earth ovens, where they build a bonfire on top of a pile of stones, heat up the stones, then pop in parcels of food wrapped in banana leaves, and bury the lot for 4 hours to cook. :shock: after which a whole crowd gathers to hold a feast. The stones have a decent specific heat capacity. This made me think that maybe gravel would be suitable to fill the fridge, or perhaps aluminium swarf (machine chippings). The problem is of course the fridge will get heavy and maybe impossible to move, so it will need a permanent location to stand in.

 

[Darkbrewer]

I'm not sure on all the math but my chiller worked pretty good. 30min from boil to pitching temp.

 

[Aleman]

I get your point. Newton's law of cooling. My idea was to put in permanent piping, and then fill the thing with something denser than water, yet with good thermal conductivity. <snip> This made me think that maybe gravel would be suitable to fill the fridge, or perhaps aluminium swarf (machine chippings). The problem is of course the fridge will get heavy and maybe impossible to move, so it will need a permanent location to stand in.

The problem is that you won't get effective/fast enough heat transfer. When I super chill my lagers from the copper, I chill using normal tap water, then when I get to 35C, I transfer the coolant to an immersion chiller in a bucket with ice water in it (Starts off more Ice than water). . . . but without stirring the ice water I only get an initial drop in cooling and then it stops . . . stir / pump the water round and I can go from 35C to 10C in 10 minutes or less . . . using a single bag of supermarket ice