The Grain Father

[Peter Smith]

http://www.grainfather.com/

Mangrove Jacks new all grain unit - its nice

[Barry]

76 minutes to rolling boil from 70deg. Yikes. I'd call that slow.

[Dene McDonald]

It was 37 litres which is probably a bit of an ask for a 2kw element. With 25 litres it was a lot faster but not sure exactly what as I didn't record it. It proved frustrating and hence I've upgraded to a 70 litre pot with a combined 4.8 kw of heating power.

Here's a video of the boil - possibly not classed as rolling. 

[Barry]

Yeah I would suggest it would be quite slow and potentially a bit light on the vigorous rolling boil. Be really interesting to see whether it is or not in real life.

Kelly (Ryan) and Mike (Neilsen) brewed with one the other day, sounded like it worked pretty well.

[Mark Weusten]

Mangrove Jacks reply

Mashing temperature to boiling temperature should take no more than 15 minutes.

Also good to note that the whole process will not take longer than 4 & half hours,

Kind Regards
Estee

Estee Slabber
CUSTOMER EXPERIENCE MANAGER
PHONE/DDI : 09 415 1124 / 963
EMAIL : [e-mail]

[Dene McDonald]

That's impressive. They must have a double skinned wall or some kind of thermal barrier.

[Peter Smith]

Just as the urns are 38L when they say 48L   you may find that the urn element is way below the rated 2kw....  Clamp the amps being used to confirm this.   Given the amount of design effort in the Grainfather there is no way its not going to hold a full rolling boil.   my stainless deathtrap boil kettle elements will pop a multibox circuit breaker, the urn never does this...  you got me all interested so I am going to clamp the urn amps ...

Ok having said all that, anyone want to buy my 48(actually 38L) urn, great condition $80?

holds sparge temps well   8)

[Richard Jack]

Unless I have forgotten all my physics (a possibility that I can't really understate, too many beers since 7th form) It must be a magic 2kW element, which is pretty cool.

Q = c_p m dT    

1g of water takes 1 calorie or 4.19 joules to raise 1°C.

So

Heat required = 4.19 * 25000 (mass of 25l of water) * 35 (delta-T between mash @65 and boil)

Heat required = 3,666,250 J

A joule is a Watt second. So you need 3,666,250 watt seconds. in a perfect system with no losses.

So:

3,666,250 (watt seconds needed)  / 2000 (element output) = 1,833 seconds for a 2kW element in a perfect system.

~30 mins.

Anyone want to check my math?

[Peter Smith]

YE  CANNAE  CHANGE  THE  LAWS  O'  PHYSICS  JIM

[Patrick]

No, I got a headache just reading that!

[Mark Weusten]

Awesome. I have just emailed Mangrove Jacks with this ( my one will probably turn up with a dent in it now :-)

[mattd2]

Looks about right to me - The only thing I would say is perhaps they are heating the mash to 77°C for mashout (during the "mash" time) which would close the gap to boiling. And maybe they are also calculating for a "normal" batch size (lets say 20 litres) not the maximum (but also ignoring the fact you need more volume before the boil to get your final batch volume).

That would give you 16 minutes for 20 litres from 77°C - 100°C. But I would say your maths / assumptions are much more on the money :)

[Scott H]

oe noe i've gone cross eyed >./p>