why 170 degrees?

why should sparge water be 170 degrees. is this just a general guideline as in "hot enough to make the sugar drain easily but not hot enough to get weird flavors", or is there another purpose.

Palmer's book goes over all of this in great detail. I can't really explain it.

For a mashout, you want to raise the grainbed temperature so that starch conversion stops. This is to maintain some residual sweetness in your beer. If you really want a dry beer, don't do a mashout and conversion will continue throughout the sparge. The reason you don't want the grainbed over 170F is that you will start to extract tannins from the grain husks. Those tannins will create a bitter astringency in your beer which is undesirable.

Some people say the higher temp makes the wort flow easier due to a lower viscosity. However, Kaiser did some experiments with lower temperature water and was still able to achieve almost the same efficiency...so YMMV. Personally, I don't worry about the sparge temp much but I shoot for 170-175F. Some people use 185F sparge water which is just fine as long as your grainbed doesn't get above 170F.

FWIW I used to have a 5 gallon cooler setup... I had NO room for a mashout infusion and didnt want to seriously overheat my sparge water. My mash, while fly sparging was about 155F... I got 80% eff.

Now I recirc. in my HERMS until my mash is about 168F... my sparge water is 173F, I dont get any better eff.

Theoretically is makes the sugars run easier, but this has been debated and tested to some degree by our studious member Kai. There is an idea that a cold sparge will give you about the same results as a 170F sparge. Some ideas need to be tested, I have seen a few "rules" fall when put to a practical test.

That being said, I DO mashout with my HERMS and I DO use 173F water to sparge with.

benl560 said:

why should sparge water be 170 degrees. is this just a general guideline as in "hot enough to make the sugar drain easily but not hot enough to get weird flavors", or is there another purpose.

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Besides the reasons already listed hot sparge water conserves fuel, taking less heat to boil.

Clonefarmer said:

Besides the reasons already listed hot sparge water conserves fuel, taking less heat to boil.

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You arent saving anything. Same water volume, same resultant temp 212F... same ammount of BTU needed in the end.

If you have a volume of water that you are heating, then heating to a set temp. say 212F. If you start with cold water, you save fuel (BTU) on that end, but have to put that some ammount of saved BTU into the boil side. Vice versa... if you start with a hotter volume, more fuel, more BTU than you can save that BTU on the boil end. Either way you have the SAME volume of water and will require the same ammount of fuel (BTU) to reach a resultant temp. You save nothing, you cannot create or destroy energy, only convert it.

The Pol said:

But you are saving fuel on heating the sparge water. Energy cannot be destroyed or created, only converted. So Id think you are using relatively the same ammount of fuel. You have to heat either the sparge or the boil more, so it is a wash.

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Good point. It just seems that way to me since I heat sparge water on a single burner on med. While the boil is done across two burners on high.

Until more evidence is provided regarding viscosity, etc. I will continue to sparge around 170. I need more proof from our resident mythbuster; Kai.

That said... The denaturing part of this equation is more relevant for fly sparging as a decent fly sparge takes about an hour, so if you do not mashout at 170ish and do not sparge around the same then extra conversion is taking place (OK, probably a poor choice of words but close enough).

The above is also more relevant to what your mash temp was. The higher the mash temp the less worry from "excessive" conversion by beta amylase since beta amylase starts to denature over 150F.

You might not save gas, but you do save time. Even if there is evidence that a cold sparge has NO difference than a hot one, I'll stick with hot. It takes a lot less time to bring wort that is around 160-175 to a boil than the same wort at 80*F.

Denny's Evil Concoctions said:

Until more evidence is provided regarding viscosity, etc. I will continue to sparge around 170. I need more proof from our resident mythbuster; Kai.

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I'm watching that space too. Kaiser has posted about the cold sparge for german beers (His special area of interest) and i will happily weigh his words and findings against the other brewing gods.

It looks like this will be an aspect of brewing that will be open for experimentation and debate in the coming months or years.


having said all that, I found that since reading kaiser's findings, i am more relaxed about coming under the sparge temp

awsome, thanks for the detail... i just didnt know how set in stone that number is. puts my mind at ease a bit.

A lot of things done in brewing are done because that's how they have done it for years. It's hard to tell sometimes if there is really a substantiated reason or not.

Look at the big breweries. They basically grind grain to flour then use a mash filter to filter out the grain husks etc. Not sure why they don't taste astringent as hell. BMC-Labbatts/Molson may taste like crap to many, but it isn't because of astringency. I do know they get about 98% efficiency.

One thing though. I can heat up my sparge water during the mash. If I sparged cold that would add time to the brew day, and lately I've been trying to shorten that up as much as possible.

Denny's Evil Concoctions said:

Look at the big breweries. They basically grind grain to flour then use a mash filter to filter out the grain husks etc. Not sure why they don't taste astringent as hell. BMC-Labbatts/Molson may taste like crap to many, but it isn't because of astringency. I do know they get about 98% efficiency.

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I'm not sure why they would be astringent. Homebrewers who do partial mashes in a nylon bag or who do all-grain brew in a bag use much finer grinds to help efficiency, and don't have any problems with astringency.

Astringency could come from too much heat, but just grinding the grain finer seems like it should help efficiency without negative effects.

I think the coarser grind is mostly a product of the sparge systems that 3-vessel all grain brewers use that can get stuck with finer grinds. They're to compensate for a problem elsewhere in the system, they're not necessarily the best way to do it.

SumnerH said:

I'm not sure why they would be astringent. Homebrewers who do partial mashes in a nylon bag or who do all-grain brew in a bag use much finer grinds to help efficiency, and don't have any problems with astringency.

Astringency could come from too much heat, but just grinding the grain finer seems like it should help efficiency without negative effects.

I think the coarser grind is mostly a product of the sparge systems that 3-vessel all grain brewers use that can get stuck with finer grinds. They're to compensate for a problem elsewhere in the system, they're not necessarily the best way to do it.

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That's a decent hypothesis...now all we need is someone to grind their grain to powder and test it out! I recently reduced the gap on my Barley Crusher from the default .039 to .031. My conversion efficiency has definitely been better, with no noticeable astringency. The crush is very fine now, with a ton of flour but I've had no problems with lautering or stuck sparges, but then again I use one of Jaybirds false bottoms that have quite a bit of surface area.

I'm leery of making the crush any finer...I'd rather not ruin a whole batch of beer just to find out if I can gain a few more % efficiency. Repeatability is a lot more important to me than high efficiency at this point.

I've done a couple brew-in-a-bag brews with very finely triple-crushed grist (and averaged about 85% efficiency into boiler) and haven't detected any astringency yet. there was a fair amount of flour, but it certainly wasn't all powder. I'm not convinced that shredded husks really present a significant possible source of tannins, provided the temp and pH are right for the mash/sparge

ericm said:

I've done a couple brew-in-a-bag brews with very finely triple-crushed grist (and averaged about 85% efficiency into boiler) and haven't detected any astringency yet. there was a fair amount of flour, but it certainly wasn't all powder. I'm not convinced that shredded husks really present a significant possible source of tannins, provided the temp and pH are right for the mash/sparge

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Well, once again the astringency from a real fine crush is one of those things we have heard repeated over and over.

Unless it somehow effects pH, my theory is that if the powderized husks are getting into the boil kettle and possibly into the fermenter this cold lead to astringency. After all, even the macros FILTER the powderized mash run off. Is this just for clarity?

I've beam meaning to chat with the former Labbatt's brewmaster that does the brewing for a brewpub here. I just have not gotten around to it. I need to pump his brain on a few things that have been brought up lately.

As for boiling grains which is related to the question of shredded husks getting into the kettle, doesn't temperature also effect pH?

I do know that if you take tea and boil it you get an extremelty bitter drink.

TwoHeadsBrewing said:

That's a decent hypothesis...now all we need is someone to grind their grain to powder and test it out! I recently reduced the gap on my Barley Crusher from the default .039 to .031. My conversion efficiency has definitely been better, with no noticeable astringency. The crush is very fine now, with a ton of flour but I've had no problems with lautering or stuck sparges, but then again I use one of Jaybirds false bottoms that have quite a bit of surface area.

I'm leery of making the crush any finer...I'd rather not ruin a whole batch of beer just to find out if I can gain a few more % efficiency. Repeatability is a lot more important to me than high efficiency at this point.

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This is where I think any astringency is probably coming from if any. Bits of grain going into the boil. I recently set up a ghetto HERMS and ground my grain as far almost as I could take it. There was a LOT of flour, none of which got into the boil, as was happening to a small degree with my lousy batch sparging technique.........So I guess I'll find out for myself in 3 or 4 weeks.

According to George Fix in "Principles of Brewing Science" (pg 51, 52). Regarding astringency from sparging:

... A general rule is to terminate the sparge when the pH of the collected wort increases much beyond 0.1 pH units higher than the mash pH. In any case it should not exceed 5.5.
Application of this general rule usually amounts to 1 to 2 Plato extract left in the gains.

If the sparge water has an alkalinity in excess of 50 mg/L as CaCO3, then the Ph will quickly approach the critical point. High temperatures also increase the extraction of undesirable compounds, the critical temperature being about 77c. Thus, best results are generally obtained with a sparge in the range of 74 to 75c and with water whose alkalinity is as low as possible (25 mg/L or below).

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Notice he does not go into specifics of why temp plays a role.

LG. Yeah, my latest batch with my RIMS (soon to be a herms me thinks) was a done with a really fine grind. The run off looked as clear as beer.

I'm using a home made grinder which I have experimented with. I now have grip tape (like sandpaper) covering both rollers and the gap is really fine. The grip tape seems to pull the husks off more than tear them into shreds. I'm having trouble actually measuring the gap. Because of wear, my grinder has some play in one of the rollers. It's set tight against each other but once you start griding the rollers separate slightly. I need to rebuild the case.

Denny's Evil Concoctions said:

Until more evidence is provided regarding viscosity, etc. I will continue to sparge around 170. I need more proof from our resident mythbuster; Kai.

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Denny - sorry if I missed it, but do you mash out? I've noticed a huge increase in efficiency (without a mash out) if I get my sparge water to ~188*F -- then again, I'm at 7000+ feet in elevation and am wondering if ambient temps and/or elevation may have something to do with it...

p.s. even when I sparge with 188*F water, my grainbed hasn't gotten about 169*F....

Yes, I mash out around 170.