Sparge water temps

[razyrsharpe]

i am curious about the effects on the efficiency (or any other aspect of the brew process) if you sparge higher than 168-170 degrees. is there a noticeable downside to sparging at higher temps, say 5-10 degrees higher than recommended? thanks!

 

[WrQth]

Sparge water being too high will result in tannin extraction from the grain husks creating a astringent flavor in the finished beer.

 

[doug293cz]

Sparge water being too high will result in tannin extraction from the grain husks creating a astringent flavor in the finished beer.

Tannin extraction will only occur if the sparge raises the pH in the grain bed to over 6. Acidify your sparge water to ~5.8 pH, and then you don't have to worry. If high temps alone could extract tannins, then any decocted beer would suffer from tannin astringency.

Brew on

 

[doug293cz]

i am curious about the effects on the efficiency (or any other aspect of the brew process) if you sparge higher than 168-170 degrees. is there a noticeable downside to sparging at higher temps, say 5-10 degrees higher than recommended? thanks!

Why do you want to sparge at higher temps? Are you batch or fly sparging?

For batch sparging, sparge water temp does not affect efficiency (ref: http://braukaiser.com/blog/blog/2009/05/12/cold-water-sparging/) as long as your conversion is ~100% complete before sparging. If conversion is incomplete, then sparging with 150˚F - 170˚F water effectively extends your mash time a little, and allows more conversion to occur, thus improving efficiency somewhat.

For fly sparging efficiency the most important factor is avoiding channeling. This is done with MLT design, and controlling the run off rate. Hotter sparge water might improve efficiency marginally due to slightly faster diffusion of sugar from wort trapped in malt grits into the sparged wort. This is just a theoretical possibility, and I am aware of no data to support this.

Brew on

 

[WrQth]

Tannin extraction will only occur if the sparge raises the pH in the grain bed to over 6. Acidify your sparge water to ~5.8 pH, and then you don't have to worry. If high temps alone could extract tannins, then any decocted beer would suffer from tannin astringency.

Brew on

I thought my post looked a little light on details, I forgot to add the pH part as a factor with water that could result in tannin extraction.

 

[razyrsharpe]

i don't 'want' to sparge at higher temps necessarily. i just want to understand the chemistry a bit better. i witnessed an accidentally high temperature sparge a couple of weeks ago and it got me thinking critically about the sparge process...