Why do we sparge with hot water?

[chaps]

2) maltose is much more soluable in hot water so it can improve efficiency (or at least time)

number two is why I do a high temp sparge. Especially with all rice grain bills things get “sticky” and using hot water helps everything drain instead of possibly coagulating. As a GF brewer one of my goals is efficiency since we start at a disadvantage so anything that helps with that I’m all for.

 

[eric19312]

I gave up sparging with 170F water a few years ago and now view it as an unnecessary step. I now sparge with hot tap water and haven't noticed a difference.

I started out using hot tap water for both mash and sparge to save time heating water but somebody in here convinced me there are some safety issues to consider. Potential metal contaminants I believe.

 

[Gruel]

I'd make sure the hot tap water is safe for human consumption, independent of brewing usage.

 

[stamandster]

I mash-out from 168-170f, I use room temp water for fly-sparge. I consistently hit 80%+

 

[bobeer]

I only sparge with 180 degree F water so it'll get to a boil faster. I used to do it with straight tap water to save time but then realized it took much longer to get it to a boil that way. As already stated, if you keep and eye on the ph and gravity you should be able to stop it before you pull anything bad out. I usually stop the sparge at 1.010... Anything below that is tossed. No issues or off flavors.

and as for all the decoction talk.. I just did one a week or so ago. There's a great Brewing TV episode about how to do it if you look it up on YouTube and that is pretty much what i did...

I mashed in at blood temp then took 2/3's of the grist back out of the mlt, boiled it for 15 minutes, then added it back to the mlt to bring it up to the next rest temp. I did that 3 times and by the 3rd time it reached 150 degrees F. After that it was a regular brew day. I just bottled it a few days ago so we'll see how it turned out soon!