Sparging at 168F....how crucial?

[MaltLicker]

Howdy - got a new fancy thermometer, and so was using it more often than usual while brewing today. 

My small infusion mash-out step that I do raised the 152F mash up to only 160F.  Enough to stop most enzymatic activity, but not optimum for lautering. 

My HLT water was about 174F when I started sparging, so I wondered since the MLT was 160F and falling, could I sparge with 180 to 182F, and assume by the time it reached the middle of the grains, it would be ~170F or even lower, with losses during the movement?   (At start of sparge, I have roughly 4 gallons in both the MLT and HLT, so I'm simply averaging the two pots.) 

I also measured the temp of the wort entering the boiler, and it was only 145F, so I know there's room to increase temps, but what's safe?   I do water chemistry and final runnings never exceed 1.012, so that's covered. 

Thoughts?

[Rep]

Howdy - got a new fancy thermometer, and so was using it more often than usual while brewing today. 

My small infusion mash-out step that I do raised the 152F mash up to only 160F.  Enough to stop most enzymatic activity, but not optimum for lautering. 

My HLT water was about 174F when I started sparging, so I wondered since the MLT was 160F and falling, could I sparge with 180 to 182F, and assume by the time it reached the middle of the grains, it would be ~170F or even lower, with losses during the movement?   (At start of sparge, I have roughly 4 gallons in both the MLT and HLT, so I'm simply averaging the two pots.) 

I also measured the temp of the wort entering the boiler, and it was only 145F, so I know there's room to increase temps, but what's safe?   I do water chemistry and final runnings never exceed 1.012, so that's covered. 

Thoughts?

I have typically brought that sparge water close to boiling and pumped it into my MLT that was drained of my first runnings.

I stir like crazy and am constantly checking the temp as I do not want to get the bed above 170F.  I may turn the HLT tank gas off, stir that water and do whatever it takes to bring that bed up to 168F.

I also am working with 30plus lbs of grain so I have some forgiveness here. 

That is why I am also looking at new strategies, as you have offered ideas on.  BTW - Thanks for doing so.  Joe

Modified to actually answer the question asked.

What is safe?  The standard appears to be no hotter than 170F.  I tend to follow standards set by brewers I respect and will follow.

Have I ever overheated my sparge water creating my grain bed to rise above 170F?  Yup.  It did not ruin my beer, but I would rather hit the target of 168F.  IE, that is MHO.

[philm63]

From what I've seen/read thus far; the greatest risk of sparging with "very hot" water (200+ F) is bursting unconverted starch granules resulting in a beer that just won't clear, and the flavor may have starchy/grainy/husky notes. This is fine if encountered during the mashing process, such as in doing a decoction because you could still hit a sacc rest to finish converting the remaining starches, but for mash-out, you won't want those added starches in the wort. I've heard from plenty of folks who sparge with 190 F water with no problems.

One thing to note; the temperature of the actual mash during the sparge is more important than the temperature of the sparge water, so one could take from this the notion you could use as hot a sparge as you wanted as long as the resulting mash does not exceed, say, 172 F.

It is also worth noting the pH should stay under 5.8 during sparging to avoid tannin extraction (sort of a misnomer, really - it's actually that polyphenolic compounds are more easily solubilized in solutions approaching pH 6.0) I address this concern by treating my sparge water with a 10% phosphoric acid to hit pH 5.5 (+/- 0.1).

[Rep]

...

One thing to note; the temperature of the actual mash during the sparge is more important than the temperature of the sparge water, so one could take from this the notion you could use as hot a sparge as you wanted as long as the resulting mash does not exceed, say, 172 F.

...

Too me, this is the most important.  Add the hot water, monitor it and cool if necessary.

[Scott Ickes]

I batch sparge and I've found that to get my mash up to 168F, I need to add water at two different temperatures.

When it's time to lauter and drain, I add my smaller sparge water addition at near boiling temperature.  This brings me up to about 160F-165F usuallly.  I add that smaller first water addition in, stir quickly to try and even the mash temperature out as evenly as possible and then let it rest for about 10 to 15 minutes.  While that is happening, the heat has been turned off on the remainder of my sparge water.  By the time I lauter and drain through my two 48 quart coolers, my remaining sparge water has been cooling down.

When it's time to add my larger addition of sparge water to the two mash tuns, my sparge water is down to about 190F.  I'm at about 165F to 168F once the mash temperature settles in after that addition.

I recently upgraded to the two cooler system to get 10 gallon capacity.  With my one cooler system previously, I actually had to wait about 10 extra minutes before adding the larger sparge water addition to let my grains cool down and sparge water cool down a little, so that I didn't overshoot 170F.  Since I have to lauter and drain two extra times to get my first runnings now, I no longer have to wait for the temps to drop.  So, my process hasn't been slowed down as I had feared.  Just more drainage time, instead of waiting for temperatures to drop time.

When I first started all grain brewing, I was adding all of my water at about 192F to 195F and I was always coming up on the low side (low 160'sF).

I'm sure that for short periods of time, some of my grains experience quite high temperature spikes that are anywhere from 190F to 210F, but I haven't noticed any graininess or astrigency in my brews.

[MaltLicker]

It seems that batch sparging has this advantage, as you learn your system, you know how high the temps can be and you stir them up and can mix the grains each time. 

With Fly sparge, the MLT is largely sealed, so once I start, I really don't know where the temperature gradient line is or how hot it is. 

I have a long thermo that I could stick thru the foam covers I use during sparging; I suppose that could be marked with tape at the proper depth that would reach the middle of the grain bed. 

[philm63]

@ Malt - I just noticed that you've identified a good point with fly-sparging; the vertical temperature gradient will shift top to bottom as you sparge.

When you start running your sparge water at temperature X, your run-off will be at temperature Y for a short period until it begins to rise as a result of the grain bed coming to equilibrium with the sparge water. If you could know when, say; the top 15% of the grain bed hit, say; 170 F, you could run the sparge a little cooler until you're done. (that'd be tricky, no? Add ice to the HLT? Cold-water injection?) The goal being not allowing the top portion of the grain bed to exceed 180 F.

This could boost efficiency. This would also require you to know how much time it takes for that top portion of your grain bed to hit 170 F, and also how long it takes until the bottom of the grain bed hits 170 F, if it can before the top portion exceeds 180 F or so. From this, you could know how hot to start the sparge, and when to start cooling it and by how much. Sounds like a lot of work, but also sounds like some fun experimentation. What's the worst that could happen? Beer?

I suspect you won't start bursting starch granules until the grains go above a certain temperature, not sure what that temperature might be, but I'm pretty sure you're safe below 180 F. It's likely closer to 200 F, but I wouldn't want to get that part wrong so I'd stay well below that. And as long as your pH stays below 5.8, you wouldn't have to worry about solubilizing polyphenols from the husk material.

[MaltLicker]

I checked that long dial thermo and it seems the perfect size to punch down into the MLT.  I will use it and reach the middle of the grain bed next brew. 

I also decided to re-work my process and heat the HLT water immediately, much hotter, and get it in the HLT right before I mash-out.   That way I'm ready to lauter as soon as it sits briefly and I vorlauf until it's clear.  That should minimize the heat lost from the mash-out infusion.   I will target starting the sparge with 180F water and see how long it takes the middle of the grains to reach 170F. 

I have known this part of my process was the sloppiest, time-wise, so this will be worth the effort on time savings if not efficiency/extraction. 

Good idea on having ice ready for the HLT if things are moving too high too fast........

[Slurk]

I've built a semi-conic MLT to guarantee a long travel distance for the water through the grain. Typically 5kg of grain = 36-38cm of travel length (I am brewing 20L batches). In the beginning I've done a lot of temperature measurements along the axis. I found out that I had considerable temperature loss. During the first 10 min the loss was the biggest with temperature differences (between top and bottom) being 9-10 Celsius finding equilibrium around 8 Celsius after 10 minutes.
After insulating the MLT I could reduce the temperature loss to 4-5 Celsius (after 10 min). Another step I've used is to warm up the Vorlauf to 76 Celsius and poor it back again on the grain bed. In stead of extra compensating for temperature loss with higher sparge temperatures the first 10 minutes, I use the Vorlauf again to find equilibrium. For me this procedure is fair enough.

R, Slurk

[MaltLicker]

I checked that long dial thermo and it seems the perfect size to punch down into the MLT.  I will use it and reach the middle of the grain bed next brew. 

I also decided to re-work my process and heat the HLT water immediately, much hotter, and get it in the HLT right before I mash-out.   That way I'm ready to lauter as soon as it sits briefly and I vorlauf until it's clear.  That should minimize the heat lost from the mash-out infusion.   I will target starting the sparge with 180F water and see how long it takes the middle of the grains to reach 170F. 

I didn't use the dial thermo during the mash - didn't want a new hole in my foam board covers. 

I did the hotter water thing though.  Almost boiling into the HLT, and it was ~185F in HLT when I started sparging.   The water drizzling from the sparge arm was about 179F, so I felt I'd hit the targets that I wanted.   The first wort into the boiler was 140F, and the total wort in the boiler gradually rose but never got above 150F, so I doubt the mash got too hot.  I should have put the thermo in the mash when I stopped the water flow, but will next time. 

Fancy Thermometer also revealed a new issue.......at end of mash, the gradient between the center of the mash and edge was ~2F.   Hardly a ME, WI or ND day, but it was colder yesterday than it has been.    Not sure what to do about that other than use a blended average number and try to associate temps with eventual mouthfeel. 

[Maine Homebrewer]

My small infusion mash-out step that I do raised the 152F mash up to only 160F.  Enough to stop most enzymatic activity, but not optimum for lautering. 

The guy at my local homebrew shop recommended single step decoction, and I've been doing it ever since. If the mash is at 150, and you're close enough to sea level that water boils at 212, removing a third, bringing it to a boil, and mixing it back in should take the whole thing up pretty close to the 168 that you want.

This method has two advantages. One is that you're not adding volume, and the second is that it gives the grain a chance to caramelize a bit which adds some nice malty flavor.  Some say the boiling bursts the grain, resulting in a higher efficiency.

[durrettd]

Several people have mentioned that one advantage of decoction is that it bursts the grains to expose more of the endosperm for conversion. But, if you do a decoction for mash-out, that burst grain won't be converted because the enzymes needed to convert it will be denatured. Because of that, on the rare occasions I've done a decoction, I've always done it before mash-out. I recently tried doing what I called an "initial decoction": I brought half my grain with half my mash water up to conversion temperature until it passed an iodine test, then boiled it for 20 minutes. I dumped it into my mash tun, added the second half of my mash water then the second half of my grain and let that convert till it passed an iodine test. Finally raised the temp to 170 for mash-out, sparged at about 170. Efficiency improved about 1 percent. I couldn't taste a difference from a single-step mash.

What am I missing here?

[philm63]

If you're not seeing a significant jump in efficiency, you may already have good efficiency for your system and may not see much difference from decoction. Efficiency can be increased by releasing more starches during the mash by decoction, and also by ensuring a grain bed temperature at mash-out sufficient to adequately rinse the sugars from the grains.

The bursting of starch granules resulting from the boil phase of a decoction will introduce additional starches which then may be converted during successive mash steps. The actual amount of starches introduced depends on several factors and I'd only be guessing if I said how much comes out - maybe only a small amount - not enough to have a noticeable effect, maybe enough to cause a haze in the finished beer that just won't clear, or maybe enough to cause grainy/starchy flavors. Because of this; if decoction is used for mash-out, it has been suggested to use only the liquid portion so as to avoid unconverted starches making their way into your kettle.

Knowing Maine does iodine checks regularly, I have to believe he has this part under control and does not suffer from residual unconverted starch issues in his brews. For folks that use decoction for mash-out and are concerned about unconverted starches - do what Maine does and grab the iodine and have a look - OR - do your mash-out decoction pulling only the liquid from the tun and boiling that and adding it back to the tun.

Another use for the decoction mash-out is where you've brewed a monster and packed your tun to the top - no room to add mash-out water! Pull some, boil, add back in - Presto!

[Slurk]

Another use for the decoction mash-out is where you've brewed a monster and packed your tun to the top - no room to add mash-out water! Pull some, boil, add back in - Presto!

Thanks philm63! Good to read that I am not the only one trying to save his mash by this method:-[
R, Slurk