Floating 'Pie Tin' to reduce boil off?

[woodwormm]

I've heard of people floating aluminium pie dishes/bbq trays etc to aid boil and reduce the time required going to boil from mash..

I had a massive boil off volume loss to my first brew. will floating a dish help reduce boil off? without hindering DMS precursors to be boiled off?

cheers

 

[manticle]

I know thirsty boy recommended it as a way of encouraging a more vigorous boil with a weaker stove.
Better off calculating system losses into recipe design -reduce heat if evaporation is too much.

 

[Charst]

how are you boiling? if you've had too much loss you are probably boiling too hard. the tray reduces the surface area and results in being able to boil with less power. sounds like the exact opposite to your drama.

 

[woodwormm]

how are you boiling? if you've had too much loss you are probably boiling too hard. the tray reduces the surface area and results in being able to boil with less power. sounds like the exact opposite to your drama.

now I think about it, thatmakes sense, I'm using a spiral burner and adjustable reg. perhaps I need to turn it down once reaches boil....

 

[technobabble66]

Hey pfs,
I've had to use 1-3 in my 30L birko urn.

Even with insulation around it, a vigorous boil with the lid on becomes a tiny simmer with the lid off. So i put in 3 small cake tins (~7cm square, each) to float on the top.
Massive difference.
The urn happily provided a rolling boil for the full 90min. Hence i'm assuming the DMS continued to disappeared at a regular rate (no mention of DMS problems in the latest case swap).

I think the boil-off of water may've been reduced slightly overall, but the problem is on one hand, it's reduced the surface area of the water but on the other hand i'm using it to increase the vigour of the boil, & hence it'll increase the vaporization rate.

I'd definitely use it for better boil efficiency; or rather, better energy efficiency.
Otherwise, if it's for reducing water losses, i'd do as manticle & charst suggest: reduce the vigour of the boil a bit &/or compensate with your calc's & add more water.

 

[Dengue]

i see nothing wrong with using a lid while bringing to the boil, though usually I find the foam cap sufficient to retain heat. Either will accelerate a rapid boilover if you don't watch it like a hawk as it approaches the critical moment.

On a separate note, you will find that a metal jacket around the skirt of the burner will save you heat loss and improve fuel efficiency, made a large difference in my case....

 

[Blitzer]

Maybe this is a stupid question, but what about floating tin foil? Would it work the same as floating a pie/cake tin?

 

[Pickaxe]

I use floating foil boats to increase boil temps on a crap stove. If I.don't, i don't get enough evaporation. Will not decrease

 

[Pickaxe]

Like with any cooking, if you want less boil off, put a lid on - not an option in brewing. Add more water, dial in evap on software. Lids don't help. Beauty of foil floater is increased boil temp allowing evap. Not a way to decrease evap.

 

[AndrewQLD]

What is your loss to boil off? I lose 6 lt an hour with my 50 lt boiler. If you lose too much then reduce you boil rate by turning down the gas.