Short mash tips/tricks

[zwiller]

Recently made the move to 30 minute mashes and what a game changer for guy like me with a young family and less brew time. Still working out the kinks. IE lower efficiency, higher FG, slight haze/astringency. My previous attempts used 1.6qt per lb and after some research I believe I need to be mashing thicker (1qt-1.2qts per lb) to improve the conversion rate. I am dialing in mash pH per BNW so I think that's covered. Just recently dialed in my mill back to .30" from .040" so it's rather fine enough I think. Think of grabbing a refractometer to keep tabs or maybe iodine? Any other thoughts?

Share you short mashing tips/tricks. Sarcasm and ridicule encouraged!

 

[IslandLizard]

I understand you're trying to find ways to cut and prioritize time. So on a whole brew session, including racking, bottling (kegging), cleaning, etc., you save a total of 30 minutes? I'd say spending the extra 30' is worth the investment, even on brew day. You get help with the kids, I hope.

A few weeks ago I did a double decoction wheat mash and it took 3.5 hours + 2 hours lautering. Maybe that's excessive, but it was fun, and kept me very busy.

 

[Hobanon]

+1 for the refractometer. Makes it infinitely easier to get precise numbers (no temp conversion or guessing at which notch your hydrometer is actually showing).

 

[broadbill]

So are you definitely seeing those side-effects of the 30 minute mash? I routinely go 30-45 minutes and see conversion and no such effects. I only go 60 min or longer on beers I want to be dry.

Check out some of RM-MN's posts on here. He is grinding super fine and doing 10 minute mashes with good results.

Like alot of things, the 60 minute mash came to be in a time when malts were much less modified and they needed the time to convert. Nowadays things are different, (the malt is highly modified and converts quickly) but we haven't stopped to ask if we could mash in a different way.

I don't agree that you should mash longer "just because"....innovation is about challenging the assumptions and looking for efficiency.

good luck!

 

[CadillacAndy]

I do short mashes as well, usually around 30 minutes. I usually double check with iodine to make sure it's done, but even after 20 minutes I've never had a failed iodine test. I most certainly still do decoctions when the style will benefit from it - usually when I'm using a large amount of Vienna or Munich malt. It's relaxing and enjoyable to me when I have the time to do it.

I have a tankless water heater, so I run off my sparge water to a kettle at 120F, treat it with campden and then sparge with the water at 120F. I only notice a decrease in efficiency of about 3-4%.

 

[MindenMan]

I recently moved from 90 Minute to 60 minute mashes, due to a negative iodine test both times. I don't know for sure yet if I'm dialed in or not. The last batch I brewed was a mild, and I hit the expected O.G.. I usually am more efficient than Qbrew says I should be, so maybe the extra 30 minutes is beneficial to my mash.

 

[stpug]

As for shortening your brewday, I would start by looking at where your time goes and adjust accordingly. Some things simply cannot be shortened or requires much extra effort to do so.

For instance, heating your striker water. Often times a burner simply cannot go higher so either you're stuck with the time it takes, or you put in the extra effort of heating two smaller containers with two burners.

Lautering and sparging: How long is your lauter? How quick do you start heating your runnings? Do you really need to sparge or can you go no-sparge? This is where I always think some time can be shaved/saved. Getting your runnings on a burner ASAP is key to saving some time. Use a lid to get to boil to speed things up, and then no-lid for the rest of the boil of course.

Boil: Keep boils at 60 minutes or "innovate" and try shorter (45 minutes maybe).

Chilling: Move to a no-chill or minimal-chill process and pitch the next day. Move your hot wort to your heat-resistant sanitized vessel and allow to cool on it's own; aerate and pitch the next day. You save the chilling time and clean up can begin much quicker. This is a process I'm considering primarily due to wasting water but I'm having a hard time coping with logistics of it - it just seems wrong (in my head) .

Overlap processes as much as possible: Grind grain while heating strike water; weight out hops while mashing; clean while boiling; prep yeast while boiling if not pitching next day; keep your equipment closer to your brew area; reduce equipment used; etc.

If you shave 5 minutes in six different places then it's a savings of 30 minutes; in other words, it all adds up.

 

[Weezy]

Double crush your grain and use a BIAB bag with your existing system and process. You'll see 5-10% boost in efficiency.

You can delay cleaning. Throw everything into a bucket of PBW water and do it the next day.

You could even boil the next day, if you really want to shorten things.

 

[zwiller]

Thanks for the comments. So it sounds pretty clear the crush is a factor. My gap opened up. I am keeping an eye on it now.

You guys doing short mashes, what is your mash thickness?

When I say that I think that brewing is work it's because I am constantly doing something. Crush grain while strike water is heating, heating sparge water while mashing, etc. Recently went to the short mash, heating runoffs immediately to boil, went 25' 3/8" to 50' IC and shaved off an hour and a half. It was incredible. I was like, why the F did I wait for all the runnings to be collected to start heating?! I am brewing more often because of this.

I could do better with lautering. I do double batch sparges and it takes 30-45 minutes. Last time I tried a single, my efficiency went way down, more than it should have been. Consequently, I am scared of the no sparge. I think a single sparge has the potential to save al ot of time and I could probably adjust recipe for efficiency loss. Any tips on a single sparge? I should mention that with my old techniques I was dialed in mid 80's.

That said, I am BJCP and I don't want to sacrifice quality. Next beer is a saison and I want it bone dry so I will go 60, but I used to do 90. A half hour hopstand on IPA's is pretty much necessary thing now too.

 

[dobe12]

+1 for the refractometer. Makes it infinitely easier to get precise numbers (no temp conversion or guessing at which notch your hydrometer is actually showing).

Temperature does actually affect gravity readings on a hydrometer. On my last brew day, I measured the gravity straight from the kettle at the end of the boil and read 1.060. After chilling, racking, aerating, I took another reading and it was down to 1.050.

I'm guessing the sample should sit for a few minutes to cool down to the same temp of the refractometer, which I've learned is accurate to about 90F.

Still trying to learn about gravity checks, refractometers, conversion times, etc. The more I think I know, the less I know.

 

[dobe12]

Thanks for the comments. So it sounds pretty clear the crush is a factor. My gap opened up. I am keeping an eye on it now.

You guys doing short mashes, what is your mash thickness?

When I say that I think that brewing is work it's because I am constantly doing something. Crush grain while strike water is heating, heating sparge water while mashing, etc. Recently went to the short mash, heating runoffs immediately to boil, went 25' 3/8" to 50' IC and shaved off an hour and a half. It was incredible. I was like, why the F did I wait for all the runnings to be collected to start heating?! I am brewing more often because of this.

I could do better with lautering. I do double batch sparges and it takes 30-45 minutes. Last time I tried a single, my efficiency went way down, more than it should have been. Consequently, I am scared of the no sparge. I think a single sparge has the potential to save al ot of time and I could probably adjust recipe for efficiency loss. Any tips on a single sparge? I should mention that with my old techniques I was dialed in mid 80's.

That said, I am BJCP and I don't want to sacrifice quality. Next beer is a saison and I want it bone dry so I will go 60, but I used to do 90. A half hour hopstand on IPA's is pretty much necessary thing now too.

Don't be afraid to add a good bit of sugar to dry out a Saison. Mash low, like 146'ish for 60-90min. And use Wyeat 3711 or Belle Saison. Start around 70F and after a day or two, let the temp rise. This is my SOP for a lot of Saisons and they usually finish around 1.003 give or take a point.

 

[charliehorse]

You might be able to split your brewing time up a bit by using an overnight mash and set everything up (burner, kettles, strike water) so that you're ready to heat your sparge water as soon as you're ready to brew.

 

[HumulusHead]

Temperature does actually affect gravity readings on a hydrometer. On my last brew day, I measured the gravity straight from the kettle at the end of the boil and read 1.060. After chilling, racking, aerating, I took another reading and it was down to 1.050.



I'm guessing the sample should sit for a few minutes to cool down to the same temp of the refractometer, which I've learned is accurate to about 90F.



Still trying to learn about gravity checks, refractometers, conversion times, etc. The more I think I know, the less I know.

When I read gravity I but both the hydrometer and a thermometer in the test tube. Armed with those two numbers you can convert to the correct SG at 60 F. Search online for hydrometer temp correction

 

[ph0ngwh0ng]

Father of three here, oldest is five.

I find that grinding grain, preparing hops and water the night before is a great time saver. Also, I get up early to turn the heat on the strike water. Last time saving tip: whirlpooling during chilling (immersion chiller with a hand drill equipped with a paint stirrer/wine degaser).

With a little help from SWMBO, I can pull off a 4 hour brew day (60min mash and 60 min boil, everything cleaned up and yeast pitched), if I don't count the strike water heating, since I do family chores during that time.

 

[dobe12]

When I read gravity I but both the hydrometer and a thermometer in the test tube. Armed with those two numbers you can convert to the correct SG at 60 F. Search online for hydrometer temp correction

Hydrometer reading corrections at elevated temperatures aren't very accurate.... at least that's what I've been told.

 

[HumulusHead]

Hydrometer reading corrections at elevated temperatures aren't very accurate.... at least that's what I've been told.

Oh, good to know! I didn't know that!

 

[fearwig]

Maybe I'm missing something, but it seems like you're "saving" 30 min of time you can still be doing something else. If you want to make things easier on brew day, mashing one night and boiling in the morning makes a bigger difference, to me.

 

[TimFarAway]

No Chill, Takes all that time totally out, but you have to take a minute to pitch the yeast the next day. I've read that some aussies can leave their wort in a HDPE cube for a month before pitching. I take my boil kettle off the flame, add a sheet of aluminum foil over the top & put the lid on, then set it in my fermentation chamber to cool to pitching temps overnight. No infections, nice clear beers so far. It does change the hops addition times, I figure in 20 minutes based off various articles and forums.

 

[stpug]

No Chill, Takes all that time totally out, but you have to take a minute to pitch the yeast the next day. I've read that some aussies can leave their wort in a HDPE cube for a month before pitching. I take my boil kettle off the flame, add a sheet of aluminum foil over the top & put the lid on, then set it in my fermentation chamber to cool to pitching temps overnight. No infections, nice clear beers so far. It does change the hops addition times, I figure in 20 minutes based off various articles and forums.

Do you simply pitch in your BK or transfer to a separate vessel first? Also, if you transfer, do you leave behind trub?

 

[zwiller]

Not sure I can commit to 2 day brewing at this point. Something to consider though. Used to me able to do a late night brew but "apparently" I am too loud going in and out of the house (brew in garage) Youngest is 16mos. With the 30 minute mash I am pushing 3 hours.

I do add 10% sugar to my saisons to good effect. 3726 all the way tho. Phenomenal yeast. Great yeast profile and not finicky like dupont.

I am pretty confident that mashing a bit thicker is gonna resolve the issues with the short mash. I have the data and research to prove it, just need to try it myself. Hoping someone would confirm.

 

[dobe12]

Not sure I can commit to 2 day brewing at this point. Something to consider though. Used to me able to do a late night brew but "apparently" I am too loud going in and out of the house (brew in garage) Youngest is 16mos. With the 30 minute mash I am pushing 3 hours.

I do add 10% sugar to my saisons to good effect. 3726 all the way tho. Phenomenal yeast. Great yeast profile and not finicky like dupont.

I am pretty confident that mashing a bit thicker is gonna resolve the issues with the short mash. I have the data and research to prove it, just need to try it myself. Hoping someone would confirm.

Well I think you were on my thread about conversion and mash times. I've only done 2 myself (2qt/lb and 1.5qt/lb) and my buddy did the same (1.4qt/lb) and we both continued to see a rise in gravity to about the 45min mark.... even though it was minimal after 30min. I can say my tests have shown about 90-95% conversion by the 30min mark. I still plan on doing 2 more. One with a very thick 1qt/lb mash and another full volume mash. Those two test should show significant differences in conversion times if there are any. I still don't think it will be as dramatic as some do.

Having said all that, I'm pretty confident that a 30min mash for an average beer is sufficient. If trying to get a drier beer, I'd still stick with 60-90min. Just my opinion though.

 

[Weezy]

What research? Got any links?

My experience is that wort density isn't that critical. mashing involves cooking the grains via a hot water bath, thereby releasing the starches...the lion share of the mash time is just getting the starches available for enzymatic conversion into sugar (which is primarily crush dependent). The actual time for the enzymes to convert the starches is a couple minutes. As long as you're using an enzyme rich base malt, there will be plenty available in wort gravities over 2.0 qt/lb.

In short...crush is much , more influential than wort density. I.e.if you mash powder, its not going to matter if the wort density is 1.0 or 2.2.

But the grain size that you can mash is a physical limitation of your system (false bottom). Use a bag; mash in minutes.

the temp of the bath really just dictates which enzymes are most active.

 

[TimFarAway]

For no-chill, I do rack into a carboy then pitch. It still only takes a half hour or so the next day. I leave as much trub in the kettle as I can while still getting all the wort. I think wilserbrewer mentioned pitching in the kettle but haven't tried that yet.

 

[dobe12]

What research? Got any links?

My experience is that wort density isn't that critical. mashing involves cooking the grains via a hot water bath, thereby releasing the starches...the lion share of the mash time is just getting the starches available for enzymatic conversion into sugar (which is primarily crush dependent). The actual time for the enzymes to convert the starches is a couple minutes. As long as you're using an enzyme rich base malt, there will be plenty available in wort gravities over 2.0 qt/lb.

In short...crush is much , more influential than wort density. I.e.if you mash powder, its not going to matter if the wort density is 1.0 or 2.2.

But the grain size that you can mash is a physical limitation of your system (false bottom). Use a bag; mash in minutes.

the temp of the bath really just dictates which enzymes are most active.

I'm agreeing pretty much 100%. That was pretty much the same point I was making. I haven't seen a difference yet in conversion time between 1.4qt/lb and 2.0qt/lb mashes. I've READ thicker mashes convert faster, but not as fully. And thinner mashes convert slower, but much fuller. I've yet to see any dramatic difference.

Link to my thread with specific numbers.

https://www.homebrewtalk.com/f36/mash-conversion-experiment-475391/

See posts #1 & #20 for specific numbers.

 

[BierMuncher]

I found taking the opposite approach ended up gaining me more non-brewing productive time. After all, nobody says that we can’t multitask during the brewing process.

In my case a 60-90 minute mash gives me time to do one or more of the following SWMBO friendly activities:

• Mow the grass
• Empty the dishwasher
• Vacuum the house
• Prep Dinner
• Go to the gym
• Run to the store
• Brush the dog…etc…etc…

I also break up the measuring/crushing/setup process from the rest of the brew session.

• I will measure out the grains in the brewshop on a Tuesday night (20 minutes)
• I will crush the grains in the driveway the following Wednesday or Thursday night (20 minutes)
• I will set up all of the brewing equipment, hook up gas lines to burners, measure out hops the night before I brew (say Friday night – 20 minutes)

Then Saturday morning I get up early, strike the mash and go do my 60-90 minutes worth of honeydo’s.
During the boil I’ll pay bills on line
During the chill I can walk away and do some more “stuff” around the house.

Total brew time from flame to clean up is 3 ½ hours on a 60 minute mash (…but I have very adequate burners and that helps).

So for me personally, working on SWMBO pleasing activities while the beer does its own thing, still allows me to dial in final malt profile through proper mash rest times. There is no way I get a very dry, very crisp blonde ale with a 30 minute mash.

 

[stpug]

For no-chill, I do rack into a carboy then pitch. It still only takes a half hour or so the next day. I leave as much trub in the kettle as I can while still getting all the wort. I think wilserbrewer mentioned pitching in the kettle but haven't tried that yet.

I'm playing with the idea of no-chill (minimal-chill) primarily to conserve water. I always feel like such a ****** watching something like 20+ gallons go down the drain just to cool 5 gallons of wort. And, as much as I'd like to capture that water, I don't need another task to deal with on brew day. I'm playing with the idea of:
-chill to 175F (about 2 minutes with IC)
-steep hops if going to
-chill to 150F (another 2 minutes if not already there after steeping)
-transfer to hdpe bucket (should be safe to 230F)
-pasteurization is complete within about 5 minutes MAX at 150F in case bucket introduced something
-into mini fridge for cooling
-pitch 12-24 hours later at desired pitching temp

I'll probably be giving this method a shot in a month or so on a non-hoppy beer to see the outcome. I figure the two chilling sessions might use a couple gallons of water which I'd be more comfortable with because during the summer it can take a ton of water to get close to my pitching temp. The winter is another story; I can chill to pitching temp in about 5-7 minutes and I'm okay with that .

 

[zwiller]

Now we're talking...

Weezy, most of what I found was on Kai's site and he was referencing Briggs and appears it dobe's thread and the consensus was what he posted here. (Thicker is faster but thinner is more complete). I also agree with him that the effect is negligible. Heck, seems like ALL of this stuff is overstated... BTW would like your comments about my crush pictured at post #46 in dobe's thread. What is clear that my mill gap opened up over time and my crush wasn't the best. Excited that dialing in my gap/crush might be the source of ALL of my issues.

SO, if thicker isn't really faster... Then, is thinner really more complete? OR one step farther, is LONGER more complete? IE dry beers

 

[dobe12]

Now we're talking...

Weezy, most of what I found was on Kai's site and he was referencing Briggs and appears it dobe's thread and the consensus was what he posted here. (Thicker is faster but thinner is more complete). I also agree with him that the effect is negligible. Heck, seems like ALL of this stuff is overstated... BTW would like your comments about my crush pictured at post #46 in dobe's thread. What is clear that my mill gap opened up over time and my crush wasn't the best. Excited that dialing in my gap/crush might be the source of ALL of my issues.

SO, if thicker isn't really faster... Then, is thinner really more complete? OR one step farther, is LONGER more complete? IE dry beers

Today I feel like time and crush are the biggest factors for conversion. But who knows what new theories and research will come along tomorrow.

 

[Weezy]

I like BM's idea! As long as your not brewing in spousal unit's kitchen.

I haven't read other thread yet but some quick thoughts:

Longer will always be more complete as you allow more time for extraction of starches. However, there is diminishing returns and you have to worry about prolonged enzymatic activity netting you more long chain sugars that won't want to ferment.

So... drier??? That's a different discussion, relying more on temp and which enzymes are active (simple or complex sugars).

More later...hate typing on phone.

 

[TAK]

I found taking the opposite approach ended up gaining me more non-brewing productive time. After all, nobody says that we can’t multitask during the brewing process.

In my case a 60-90 minute mash gives me time to do one or more of the following SWMBO friendly activities...

(Insert your favorite SWMBO friendly activity)

So for me personally, working on SWMBO pleasing activities while the beer does its own thing, still allows me to dial in final malt profile through proper mash rest times. There is no way I get a very dry, very crisp blonde ale with a 30 minute mash.

I 100% agree with this. My last brew day I let my mash do it's thing while I partook in certain SWMBO pleasing activities, and there's no better way to spend a 90 min mash.

 

[zwiller]

All good stuff! Thanks. I have done the SWMBO while brewing thing. It works. You guys are lucky, my to do lists are not like yours... Mine are like, strip and seal the deck, edge and mulch landscaping... Dirty stuff that I would prefer to not mix into the brew session. I forget how many of you are independently wealthy and have staff or hire people for things like this.

 

[broadbill]

For no-chill, I do rack into a carboy then pitch. It still only takes a half hour or so the next day. I leave as much trub in the kettle as I can while still getting all the wort. I think wilserbrewer mentioned pitching in the kettle but haven't tried that yet.

You aren't racking hot wort into a glass carboy are you?

 

[TimFarAway]

No, I rack 70* wort into plastic. Boiling liquid into glass would be asking for trouble.

The aussies (and a few of us on HBT) will pour near boiling wort into an HDPE cube and let the hot liquid sterilize it. Then seal it up, and let it sit until it is cooled down and ready for yeast. The main reason they do this is to conserve water in places where every drop is precious. Once I find a cube I like, i'll probably start doing that myself.

 

[roastquake]

I'm not a parent, I just got sh#t to do, so I made my brewdays shorter. My method is BIAB/no-chill:

1. heat water while crushing grains fine. 30 min.
2. mash 50 min
3. mash-out (great efficiency booster) 20 min
4. boil 40 min. (no-chill method adds 20 min to each hop additions, see the fifth post on this thread
5. minimal equipment = minimal cleanup. 30 min
6. let the wort cool in the kettle or HDPE container for 24 hours, aerate and pitch the next day.

That makes my brew day about 3 hours, give or take.

 

[zwiller]

More power to you no chill guys. Scares me. That said, usually summer beers get the IC for a few minutes down to 80-90s and into the fridge t-stat set 30F overnight. That said, even if I go nuts and try to hit pitching temps my whole chill time is 15-20 minutes tops and water is cheap. I can the totally see the no chill thing would be valuable to the Aussie dudes and those in hotter climates/water costly area.

After digging deeper for info regarding the crush and gap width, I needed to convert alot of the published specs from metric to imperial and was very surprised with the numbers. I recall the standard gap being .036" (JSP mill). Kai seems to advocate a crush of .019" nearly half than the standard. Other sources were in the low .020"s as well. I even found sources that many pro brewers actually pulverize the malt and use mash pads to reduce lauter problems. Seeing that the crush is probably the primary variable to influence rate of conversion I plan to go finer, like .020"-.025". Of course, double milling at is an option too. In any event, it is clear my crush was less than desirable for a typical mash, yet alone a short mash.

 

[broadbill]

More power to you no chill guys. Scares me. That said, usually summer beers get the IC for a few minutes down to 80-90s and into the fridge t-stat set 30F overnight. That said, even if I go nuts and try to hit pitching temps my whole chill time is 15-20 minutes tops and water is cheap. I can the totally see the no chill thing would be valuable to the Aussie dudes and those in hotter climates/water costly area.

After digging deeper for info regarding the crush and gap width, I needed to convert alot of the published specs from metric to imperial and was very surprised with the numbers. I recall the standard gap being .036" (JSP mill). Kai seems to advocate a crush of .019" nearly half than the standard. Other sources were in the low .020"s as well. I even found sources that many pro brewers actually pulverize the malt and use mash pads to reduce lauter problems. Seeing that the crush is probably the primary variable to influence rate of conversion I plan to go finer, like .020"-.025". Of course, double milling at is an option too. In any event, it is clear my crush was less than desirable for a typical mash, yet alone a short mash.

Having been on this board a few years, I remember a couple of years ago the saying around here was "Crush till you're scared".

It came from multiple discussions where the idea that fine crush caused astringency was debunked, and that stuck sparges weren't as big of a threat as they were assumed to be. Worst come to worst, use rice hulls.

Everyone seemed (and still are) hung up on getting good efficiency, if for nothing else to brag about it on here. So the way to do that is to crush the hell out of that grain.

 

[RM-MN]

I'm not a parent, I just got sh#t to do, so I made my brewdays shorter. My method is BIAB/no-chill:

1. heat water while crushing grains fine. 30 min.
2. mash 50 min
3. mash-out (great efficiency booster) 20 min
4. boil 40 min. (no-chill method adds 20 min to each hop additions, see the fifth post on this thread
5. minimal equipment = minimal cleanup. 30 min
6. let the wort cool in the kettle or HDPE container for 24 hours, aerate and pitch the next day.

That makes my brew day about 3 hours, give or take.

I like your list but I do some things differently. I use a Corona style mill and I have it set so tight the plates are rubbing when it is empty. It sounds terrible but that gets my grain particles down.

With the very small grain particles I only mash 10 minutes. Iodine test says it's done, the OG says it's done, the FG says I mashed too long.

Mash out is needed for fly sparging, not any other type of sparging. If you are getting an efficiency boost its because you've added more time to the mash and got more sugars because your grain wasn't milled fine enough.

With the 10 minute mash, no chill, just dump into the HDPE fermenter bucket when the boil is done and clean as I go, I have everything cleaned and put away in 2 hours 10 minutes. I'd need a faster way to heat to reduce the time any more.

 

[broadbill]

With the very small grain particles I only mash 10 minutes. Iodine test says it's done, the OG says it's done, the FG says I mashed too long.

I assume when you say this you are referring to over-attenuation. Do you do anything to prevent this?

Mash out is needed for fly sparging, not any other type of sparging. If you are getting an efficiency boost its because you've added more time to the mash and got more sugars because your grain wasn't milled fine enough.

I mash out to inactivate the enzymes before sparging. Otherwise I found my mash will continue to convert as I collect runnings, unless I begin to heat immediately (which I try to do but I'm usually shuffling pots of runnings around to do this).

With the 10 minute mash, no chill, just dump into the HDPE fermenter bucket when the boil is done and clean as I go, I have everything cleaned and put away in 2 hours 10 minutes. I'd need a faster way to heat to reduce the time any more.

You do BIAB, right?

 

[fearwig]

Mash out is needed for fly sparging, not any other type of sparging. If you are getting an efficiency boost its because you've added more time to the mash and got more sugars because your grain wasn't milled fine enough.

Actually it's probably because you got your first runnings up to 170 just like you do (or should) the rest of your sparge water, and so they dissolved more sugars. If your sparge water is too cold, efficiency always suffers. No difference between that and your mash water.

 

[QuercusMax]

Actually it's probably because you got your first runnings up to 170 just like you do (or should) the rest of your sparge water, and so they dissolved more sugars. If your sparge water is too cold, efficiency always suffers. No difference between that and your mash water.

I've certainly found that to be true. I do a single batch sparge with a mashout, normally mash at about 1.25 qts/lb. Once my 1-hour mash is done, I add enough boiling water (usually 1-1.5 gallons, depending on how much grain) to get to 170, then run out my first batch. Then I add enough 170 degree water to get up to my preboil volume.

If I add 1-1.5 gallons of 170-degree water instead of boiling water, I lose some efficiency. It's definitely not due to a longer mash. Hotter water can dissolve more sugars than cold water - my son just learned that in 4th grade chemistry.

Now, if you do a triple batch sparge, and do the last batch with cold water, it probably won't make much difference, since the amount of sugars you'll be dissolving in the third runnings will be so small they'll easily dissolve even in cold water. I've done that a few times when I mis-measured my sparge water, and it came out just fine.