Interesting video featuring cold sparging

[Kev888]

Well I think it is as old as the house, since it is too big to get through the loft hatch, so over 50 years old now, made from galvanized iron I think. No mesh on the outputs.
The hot water tank is ~20 years old as I replaced the direct feed tank when my back boiler failed about then.

I was brought up never to drink from the hot tap, or to use that water for drinking when cooled. So I still do. It would probably be OK, but I would rather be safe than sorry, I have enough health issues without adding to them.

A lot of hot water systems are still like this, or not much more advanced. The owners haven't felt any need to replace them because (as you say) it is simply known and accepted that the hot tap isn't for drinking water (until recently, anyway). Of course, its unlikely you'll find a huge pigeon in it (if anything, more likely to be insects or small rodents that can't climb out), but it was never designed to provide drinking water, certainly by todays standards, so in my opinion you are correct to continue with that distinction. TBH with respect to beer I wouldn't expect the wort to be full of pathogens after a 90min boil, but that isn't so say other contaminants like lead or verdigris won't be present in a hot water system of that age.


Anyway, going back to the OP: in a mash tun I like the sparge water to be warm to improve the rinsing effect and help get it through the sticky malt bed. But in a bag I don't see any reason why cooler water wouldn't be a fair choice for reasons of simplicity. In general its not really the same sort of thing (as say a 40-minute fly sparge would be), more just flushing out of freely available wort retained in the grain bag. Its possible that cooler water may even be safer in a quick/improvised/crude sparge with a jug or something, since its less likely to rinse out tannins in parts of the grain bed/bag that could otherwise be over-sparged.

It is often suggested that one other reason for a warm sparge is to halt enzymatic activity, but in my experience thats not always possible to achieve anyway without the sparge being dangerously hot, and at home brew scales the kettle will be bringing things up to temperature in fairly short order anyway.

Cheers
Kev

[JamesF]

We don't get pigeons in our loft. They're too big to fit through the holes. The starlings can though. Our cold water tank is closed by a tight lid and insulated too, so they'd probably need tools to get inside. These days it only feeds the toilets and washing machine anyhow; everything else is directly off the mains.

James