Cold water sparge

[Kaiser]

Who says you need to sparge with hot water to get good efficiency. I just did a batch sparge with cold water (single sparge, two run-offs) and hit 86% efficiency into the kettle. This is about what I got with the same recipe last time when I sparged with hot water.

Recently I have been doing more thinking about efficiency and I found no reason why a cold sparge should hurt when batch sparging if all your conversion is done during mashing and no further conversion happens during lautering. In this case I hit close to 100% conversion efficiency in the mash so there would not have been anything to be converted during the lauter.

The wort never cleared up though. I assume that this was basically cold break that formed due to the lower sparge temp

Kai

 

[Yooper]

Who says you need to sparge with hot water to get good efficiency. I just did a batch sparge with cold water (single sparge, two run-offs) and hit 86% efficiency into the kettle. This is about what I got with the same recipe last time when I sparged with hot water.

Recently I have been doing more thinking about efficiency and I found no reason why a cold sparge should hurt when batch sparging if all your conversion is done during mashing and no further conversion happens during lautering. In this case I hit close to 100% conversion efficiency in the mash so there would not have been anything to be converted during the lauter.

The wort never cleared up though. I assume that this was basically cold break that formed due to the lower sparge temp

Kai

Well, about about the talk that a hotter sparge helps efficiency by keeping the sugars more "fluid" and allowing more efficient lautering?

 

[Beerthoven]

When you say cold, how cold do you mean? 50F or 120F? Or does it not matter?

 

[Kaiser]

The water was from the tap. So it was at 54 F.

There is little change in fluidity in the 2nd and later runnings b/c they are lower gravity anyway. The main reason why a hotter sparge helps is b/c it causes more protein coagulation which increases the particle size and that improves the flow rate more significantly than a less viscous wort. But in batch sparging I don't really have to worry about that as long as it flows and even though I didn't time the run-off time it didn't seem to take longer than usual.

Kai

 

[Kaiser]

Here is the efficiency breakdown using my spreadsheet (http://braukaiser.com/documents/efficie ... ulator.xls)

 

[WortMonger]

Interesting... very, very interesting! I'll be staying in touch with this thread.

 

[fivehoursfree]

Makes it quicker to bring the wort up to a boil if the sparge water is halfway there.
<Shrugs>

 

[bendavanza]

subscribed

 

[Kaiser]

Makes it quicker to bring the wort up to a boil if the sparge water is halfway there.
<Shrugs>

Yes, and that's why I will stick with the hot sparge.

Kai

 

[McKBrew]

Cool. I think some people are just brewing gods with the magic touch. I'm betting Kaiser would come and brew at my house using the exact same ingredients and outdo my efficiency by 10-15%. I bow to you my lord.

 

[WortMonger]

What is thy bidding my master?

 

[FlyGuy]

Bizarre. Have you replicated it yet?

Sugars are known to be more soluble at higher temps. Lots of people have reported that a mash-out or hot batch sparge increased their efficiency. It seems logical that this is a likely mechanism for it. But your test (although unreplicated) suggests otherwise. But it DOESN'T explain the predominance of results by the masses. Any suggestions Kaiser?

Also, out of curiosity, is that a typical efficiency for you, or did it drop slightly?

 

[Kaiser]

Sugars are known to be more soluble at higher temps. Lots of people have reported that a mash-out or hot batch sparge increased their efficiency. It seems logical that this is a likely mechanism for it.

For a while now, my position on this has been that this is not a solubility problem. Even cold water can hold a lot of sugar. Just mix 1 cup of water with 1 cup of sugar and even at room temp the sugar will dissolve completely. It may take a little more time. And wort (even the first wort) is much weaker than that simple syrup. Once starch has been converted to sugar these sugars won't come out of solution and wait to be dissolved again by hot sparge water. Hot sparge water may speed up the process of leaching extract from the grits in the grain but the amount of sugar left in there is small compared to the sugar that is already dissolved in the sweet wort.

In my opinion there are other forces at work. I believe that brewers who see an efficiency jump when using hot sparge water cause more starches to be converted. I.e. they actually improved conversion efficiency and not lauter efficiency. For me the conversion efficiency was close to 100% and there was no room for change there.

But I don't think that this experiment will change the way I brew. There are still benefits to hot sparging. Getting to a boil faster is one of them and I haven't tasted the beer yet which means there can still be a surprise. But if this works and the beer is fine then I can see these pros:

- don't worry if you forgot to heat your sparge water
- BIAB brewers can actually sparge the grain in a cold water bucket.

But your test (although unreplicated) suggests otherwise.

I'm not sure If I'm interested in repeating this anytime soon. There is so much more I want to try that may actually make a difference in my brewing.

Also, out of curiosity, is that a typical efficiency for you, or did it drop slightly?

I generally get 85-87% on that size of a beer.

Kai

 

[FlyGuy]

I'm not sure If I'm interested in repeating this anytime soon. There is so much more I want to try that may actually make a difference in my brewing.

But that's the beauty of having this community -- perhaps others can give it a try and see what they get! That's even better replication because its independent. But I hear you.

Neat idea, anyways. Challenges the conventional wisdom -- typical Kaiser style!

 

[FlyGuy]

Kaiser, another question -- what was your liquor-grist ratio for this brew. You tend to mash pretty thin, don't you? I wonder if that had any influence on your results? (I.e. I wonder if a temperature difference would be more apparent to someone who mashes fairly thick, say at 1.25 qts/lb.)

 

[Bobby_M]

Ok, so empirically my efficiency ALWAYS drops by 5-8% when I fudge my sparge temps on the low side. If I understand your hypothesis, it may be translated to "if a hot sparge boosts efficiency it is probably due to promoting continued conversion for at least part of the sparge". Is that what you're saying?

To flyguy's point, I mash around 1.5qt/lb which I'd consider in the midpoint of the range.

Certainly one easy way to confirm this is (and isolate only to sparge temp) to split the same exact mash into two lauter tuns and sparge each with the same volume of water, one cold, one hot and measure gravity.

 

[pjj2ba]

I think Kaiser's observations are right on. The sugars are plenty soluble in cold water, heck look a LME! I think one issue is simple fluid dynamics. The water just flows better, which can be important in bigger beers.

I always wonder about flavor compound extraction versus starch conversion. Is one faster than the other? I'm very curious to see how your beer turns out. If the flavor is there, then flavor extraction is at least on par with starch conversion. If you find it lacks in the taste, this might indicate that extraction of the flavor compounds is a slower process that would benefit from more heat. One of these days I want to try an intentionally low efficiency brew to examine the affect on flavor. I'd use extra grain and just do a really quick mash so the OG is low, but I'm hoping the flavor compounds are quickly extracted from the grains. I'd use, say 2 extra lbs of base malt to get the same OG as I would from my normal recipe.

 

[FlyGuy]

While sugars may be soluble in both hot and cold water, I don't think that is really the point. The solubility of sugar is directly related to temperature. Higher temperatures will necessarily dissolve more sugar, pulling them away from the grist and into solution more readily, which is a goal when sparging. The relevant question is how significant is this effect, and is it enough to make an appreciable difference in your measured efficiency to the kettle? That I am not so sure one.

Kaiser's results suggest no (but it was only one trial, and therefore might have been a spurious or chance event). Dozens of homebrewers have run the reciprocal trial (i.e. INCREASED the temp of their sparge water and seen their efficiency go up) to provide conflicting evidence.

Like Kaiser, I am curious why this can be. I suspect it may have more to do with the viscosity of the wort and the adhesion of those 'sticky' sugars to the grist, especially when one mashes fairly thick (say around 1.25 qts/lb). But it is likely a combination of many factors.

Kaiser -- why don't you move this to the Brew Science forum? I think this thread might get more attention there. And for anyone browsing the All Grain forum, they will still spot this topic.

 

[Laughing_Gnome_Invisible]

Wow!! I mean, just wow! I only clicked on this thread because I thought it would have good comedy value. I almost fell off my chair when I saw that it was started by Kaiser.

This is a definite thread to watch from now on. Subscribed, prosted, rated and stapled to a passing hobo for future reference!

Oh yes! Why only batch sparging? Would it not be similar for fly sparging?

 

[Kaiser]

The mash thickness was 4:1 (4 l/kg or ~2 qt/lb) and I mashed in the kettle on the stove (Hochkurz: 63C,30min -> 70C, 40 min -> 76C, 15 min). There is a lot of stirring during heating and the long rest at 70 really boosts the conversion. I think that all the (good) flavor is extracted during mashing and present in the first wort. Sparging only rinses out the wort that is still clinging to the spent grain and it also leaches out undesirable compounds.

A viable experiment would be to take the spent grain after running off the first wort and put one sample into a paint strainer into hot sparge water and another sample into cold sparge water. let it sit for 10 min, strain and test the gravity. This should be done a mash that has close to 100% conversion efficiency and one that has only 70-80% conversion efficiency.

Bobby, you should gather the numbers necessary for my efficiency spreadsheet and see how much is lost in the mash and the lauter. I think that if there is significant conversion happening during the sparge the final sum should be more than 100% as some of the starches, that were considered lost after mashing, are actually converted and will show up as additional extract in the kettle and/or additional extract present in the spent grain.

Kai

 

[FlyGuy]

An interesting experiment would also be to conduct a factorial design where one simultaneously manipulates the thickness of the mash and the sparge water temp. To do this, one could split a batch, and add more water to the second to increase the liquor-grist ratio. Mash both at the same temps, and at the end split each. Then do what Kaiser suggests, and put one sample from each in cold water, and the other sample from each in hot water. Check the gravity of each after 10 mins or so.

Treatments:
1. Thick mash, hot sparge
2. Thin mash, hot sparge
3. Thick mash, cold sparge
4. Thin mash, cold sparge

I would hypothesize that #3 would have the lowest gravity. The rest will probably be fairly close, I bet (borrowing from Kaisers results).

 

[RCCOLA]

Who says you need to sparge with hot water to get good efficiency. I just did a batch sparge with cold water (single sparge, two run-offs) and hit 86% efficiency into the kettle. This is about what I got with the same recipe last time when I sparged with hot water.

Recently I have been doing more thinking about efficiency and I found no reason why a cold sparge should hurt when batch sparging if all your conversion is done during mashing and no further conversion happens during lautering. In this case I hit close to 100% conversion efficiency in the mash so there would not have been anything to be converted during the lauter.

The wort never cleared up though. I assume that this was basically cold break that formed due to the lower sparge temp

Kai

I've read a bit on your site where you have proven that most of the standard published brewing assumptions are not necessarily true or have little merit.I too have a hard time believing that .004 crush difference would make someones eff. jump 25pts. or that 5degrees sparge water temp would have similar effects.
So,my question to you is--How do you approach technique to brewing different styles?Do you use the old (this is how your'e supposed to brew this style guidelines)or something entirely different?

 

[Kaiser]

So,my question to you is--How do you approach technique to brewing different styles?Do you use the old (this is how your'e supposed to brew this style guidelines)or something entirely different?

Most of my techniques are based on German brewing practices old and new. It is not that I’m not interested in other styles, I just want to keep my focus so I can go more in depth.

This being said, I’m a big proponent of understanding brewing techniques to a point where you can evaluate traditional and modern brewing techniques. To me it is important to understand why things were done in a particular way and why they may be done differently today. Some old techniques may have flavor benefits that you don’t get with the modern techniques but they have been abandoned in modern brew houses b/c they don’t fit in. But as a home brewer we are not bound by these restrictions.

While I’m a proponent of thin and stepped mashes I only push them for German styles. If you brew an English ale for example you should use an English malt with a thick single infusion mash. There might be a flavor difference that is part of the character of these beers.

I’m not a big fan of a one-size-fits-all approach unless your system really requires this.

Kai

 

[RCCOLA]

Thank you sir for your prompt reply.

 

[FlyGuy]

While I’m a proponent of thin and stepped mashes I only push them for German styles. If you brew an English ale for example you should use an English malt with a thick single infusion mash. There might be a flavor difference that is part of the character of these beers.

That brings up another interesting point. I wonder how much the gravity and fermentability of the wort play a role as well. I suspect that higher gravity brews, especially ones with a higher proportion of unfermentable sugars like some of the bigger English ales, might show a greater effect of hotter sparge temps.

 

[Reverend JC]

From what I understand on the topic most home brewers need to use a heated sparge because when constructing their frankenstein sparge manifolds most understand very little about bluid dynamics and flow rates. Thus the hot sparge "loosens" the sugars from the grain and helps them flow more easily to the boil kettle. I have attmepted something similar with cold water and it seems that with pure dumb luck I have created a sparge mainfold that has excellent flow as my eff. has not suffered from the cooler temps. But, as stated, it then takes longer to get to a boil.

What does hurt my eff. when fly sparging is sparging way to fast. The grain bed then starts to channel and I miss a good deal of sugars.

 

[pompeiisneaks]

Here's some more anecdotal evidence for the cold water sparge theorists... I didn't do a cold water sparge... just nowhere close to the normal...and go the best eff I've had yet... I mashed at 154, and sparge I could never get over 158. I got 80% eff... Thus the hot water to get the sugars has more damning counter evidence . That being said, its just one guys experience, so YMMV.

 

[scinerd3000]

Kaiser- how are you calculating conversion efficiency? I see the excel calc but im talking about doing so long-hand.

 

[ghack]

I think one of the key points is not to sweat your sparge water temperatures so much. "Relax, don't worry, have a homebrew" is vindicated yet again.

 

[Kaiser]

Kaiser- how are you calculating conversion efficiency? I see the excel calc but im talking about doing so long-hand.

Sorry for the delayed answer. But here is more detail: Understanding Efficiency - German Brewing Techniques

Kai