Batch Sparge Water Temp

Hey all…

I started out batch sparging with 168 degree water several years ago because that was the default in beersmith but was having trouble with efficiency.  Someone in my local brew club suggested I raise my sparge temp to 180-185 and wallah… 70-75% efficiency.  I’m wondering what effect sparge water temp has on the finished beer if any…

My understanding is that the higher sparge water temperature reduces the viscosity of the liquid that is still in the mash and as a result makes it  easier to rinse more sugars from the grain bed.

If that is true, then ask Kaiser (global moderator here) how he was able to get 80-85% efficiency with a cold sparge.

I guess I’m more interested in how sparge temp affects the profile of the finished beer.  Are you possibly suggesting that the 180 degree water would make for a thinner bodied beer as opposed to a lower temp?

Nope. I’ve sparged from 165 - 190F (batch sparging) and noticed no change to the final flavor profile.

Caveat to the above; watch the pH and you’ll have nary a problem sparging with high temps. One thing that can happen when sparging over about 170 F is the extraction of tannins (aka; the solubilization of polyphenolic componds) but this is primarily a function of pH rather than temperature.

Tap water above 170 F can be less than ideal for sparging due to its pH being in the 6.5 to 8.0 range (typically), but lower the pH to the 5.5 to 5.8 range and you technically can have it up to boiling temps and you won’t extract tannins. I stick to around pH 5.5 at 190 F for my batch sparge.

Absolutely, pH is critical. I was assuming good pH, but it is worth mentioning again - if pH is good, you can sparge at whatever temp you like and not extract tannins (see decoction mashing where grain is boiled with good results), but if pH is bad, a sparge of any temp will very likely extract tannins.

The decoction doesn’t extract tannins, therefore a hot sparge won’t extract tannins theory is debunked.

From BYO:

Decoction mashing extracts more tannins than an infusion mash. Along with gelating the starch, boiling the mash extracts husk compounds, including polyphenols (tannins). The level of tannin extraction, however, is fairly low and some maintain that this low level actually benefits the flavor of the beer. If a low, pleasing amount of tannin extraction is a piece of “decoction mash character,” then simply adding Munich or melanoidin malt would not capture that character exactly.

Homebrewers used to infusion mashing may wonder how a decoction could be boiled without extracting a large amount of tannins and yielding a very astringent beer. After all, when lautering, they are repeatedly told that their grain bed temperature should never exceed 170 °C (77 °C). The key to understanding this apparent discrepancy is understanding when tannins are soluble in wort. Increased heat and increased pH both favor tannin extraction. At lower pH values, such as those found in a thick mash, tannin extraction from grain husks is minimal even at boiling temperatures. At higher pH values — such as those in a grain bed that has been extensively sparged — excess tannin extraction occurs at a much lower temperature.

I usually batch sparge with 190 F water.  Even then the temperature always equalizes below 168 F so there is almost zero risk of tannin extraction.

Decoctions also have a high gravity level. Somewhere I read that also helps to minimize tannin extraction.

Even with adjusted pH sparge water you need to watch the gravity of the runnings, and stop in the 3 or 4 Plato range. If you go too low you can still get astringency - taste those last runnings. I know this from experience.

Your quote supports the argument that pH is key and that decoction doesn’t extract an unpleasent (fault level) amount of tannins. so not so much debunked as clarified. It’s all about flavor thresholds.

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If you look at charts of solubility of sugar in water vs. temp, there’s so little difference between 168 and 190 F you can pretty much discount it.

I always use sparge water in the 185-190F range.  Not to increase solubility, but more to ensure complete conversion.  r maybe because it’s a habit!  ;)  The hotter sparge temp seems to not change the flavor or body of the beer at all.  At least not that I’ve noticed over the course of 400+ batches.

Yes, it should be noted that decoction doesn’t extract objectionable tannins.  Note also that the article says “At lower pH values, such as those found in a thick mash, tannin extraction from grain husks is minimal even at boiling temperatures. At higher pH values — such as those in a grain bed that has been extensively sparged — excess tannin extraction occurs at a much lower temperature.”  So I stand by my statements with the addition of the word “objectionable”

What you’re referring to is gravity as an indicator of pH.  The way I see it is that with higher gravity, the grain retains more buffering ability.

My point was one can not draw conclusions about sparging based on decocoction.  They are different processes with different variables.  I have no problem believing a hotter sparge at the right pH can produce unobjectionable results.

But isn’t it basically the same process?  Heating the grains above what’s usually considered a “safe” temp?  How hot would you say you need to be to get tannins even with a “safe” pH?  I’ve accidentally sparged with water in excess of 200F and didn’t get objectionable tannins.

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But the sparge water is adjusted to, 5.5 with acid, and it has been RO for years.