Spent Grains Really Spent?

[GrowleyMonster]

I just ground 14lb of Viking Pale 2-Row and a pound of Briess Chocolate 350 for my second BIAB batch and my biggest beer to date. My first BIAB batch I just tossed the grain after mashing. But this is a bigger batch, and I am wondering if there are enough fermentables left in the mashed grains to get another couple gallons of wort out of them, with reasonable gravity. Honestly I am okay with anything over 4% ABV, if the alternative is to just toss it. A lighter beer can be nice when working in warm weather and this is New Orleans, after all. I am thinking maybe after draining the bag over the kettle, I might give it a soak in a couple gallons of warm water and maybe sparge it a bit before discarding. What say you experienced brewmeisters? Would this be worthwhile?

The reason I am thinking this might be a thing is that with higher gravity wort, more sugars will be left in the grain, and clear water ought to recover a fair amount of that. 15lbs of mashed grains ought to be good for SOMETHING, right? I don't have chickens.

 

[dwhite60]

All you can do is give it a try. There's certainly something left there. Might try a gallon batch with the same process and recipe scaled down and see what you get.

All the Best,
D. White

 

[IslandLizard]

Assuming you had complete conversion, all starches turned into sugar and dextrins.

Measure the gravity of a some of the runnings from the lifted grain bag. Hydrometer needs 3-4 oz, refractometer 1 drop.
Estimate how much wort is trapped in the grist.
Start with 0.12 gallons per pound of grist (give or take), but the real amount largely depends on the grist, texture, and how much you squeezed or wringed out the bag.

15# of grain holds onto 15 * 0.12 = 1.8 gallons of wort at your preboil gravity.

Either perform the following, or just do a dry run on a calculator:
Sparge 2x or 3x with a gallon or a gallon and half of water to rinse most of the wort out. Use your kettle or a large bucket. Stir well, drain as much as you can, squeeze if you want. Then do it again (and again). Take gravity readings of each of the runnings. After the second or third time you're encountering diminishing returns.

 

[foolsbrew]

I think it was calculated to be 10%. I.e. add an additional 10% to your grain bill if you are not sparging.

 

[madscientist451]

No, 15 lbs of spent grains aren't really spent at the homebrew level. You can put another 4.5 gallons of water through the grains, boil for 90-120 minutes and make 3 gallons of OK beer to drink or you can save time and just chuck it out. You can do all kinds of other things like add sugar, honey or extract to bump up the alcohol if you want to. I'd say go ahead and try it and decide later if it was worth your time and effort.

 

[fastengine]

Use hot water to help dissolve those sugars. I did a second beer on a stout all grain I made yesterday hitting 78% efficiency and while I was getting the boil going I covered my grain with 3 gallons of 180 degree water for about 1.5 hour and drained slowly and pulled 3 gallons of 1.022 wort from my mash tun. I would assume that BIAB is going to leave a lot more sugar in the grains, being less efficient. I add golden light LME and made a 1.040 beer that took much less time than the first beer, and cost very little to do.

 

[wilserbrewer]

You also don’t have to limit yourself to beer 1 and beer 2, or first and second runnings.

You can make extra first runnings, and add some of that to the second runnings to bump gravity of the second runnings.

Blending the runnings to tailor gravity.

For even greater efficiency, one could sparge twice and split the middle runnings between the two batches.

 

[doug293cz]

Use hot water to help dissolve those sugars. I did a second beer on a stout all grain I made yesterday hitting 78% efficiency and while I was getting the boil going I covered my grain with 3 gallons of 180 degree water for about 1.5 hour and drained slowly and pulled 3 gallons of 1.022 wort from my mash tun. I would assume that BIAB is going to leave a lot more sugar in the grains, being less efficient. I add golden light LME and made a 1.040 beer that took much less time than the first beer, and cost very little to do.

There are no sugars to dissolve after a mash. All sugar is in solution as it is formed. No need to use hot water.

Brew on

 

[doug293cz]

15 lbs of grain with 8 gal of strike water, 0.1 gal/lb grain absorption will give you 6.5 gal of 1.060 wort pre-boil (assuming 100% conversion efficiency.) The first wort will have 8.45 lb of extract (mostly sugar), and the spent grain will still have 3.09 lb of extract. If you dunk sparge the grain with 3 gal of water, you will recover 3 gal of 1.026 - 1.027 wort. If you sparge with 2 gal of water, you will recover 2 gal of 1.032 - 1.033 wort.

Brew on

 

[fastengine]

There are no sugars to dissolve after a mash. All sugar is in solution as it is formed. No need to use hot water.

Brew on

I guess I should have said extract the sugars, I know from experience that hot water makes a difference sparging.

 

[doug293cz]

I guess I should have said extract the sugars, I know from experience that hot water makes a difference sparging.

No, it doesn't. Using hot water can help you create more sugar, if your mash conversion is incomplete when you start sparging, but hot water will not improve lauter efficiency.

Brew on

 

[fastengine]

I read the article and the conclusions, I guess we will agree to disagree. I might be wrong but I learned from the old school brewing books and it seems that everything we used to do has been proven wrong or unnecessary. Hopefully the OP still makes his 2nd running beer, I believe he'd be missing out on a nice easy drinker.

 

[GrowleyMonster]

Thanks for all the great answers!

Here is what I ended up doing, as I was brewing while some of the answers were coming in.

I mashed the grain in 7.5 gallons with water at about 158f starting temp. Given a choice of over 5 gallons of wort or under 5 gallons, I got to go with under, so it fits in a corny with a little head space in there. So I figured 7.5gal was enough water. I mashed for an hour, pulled the bag, drained (sure was heavy holding it up so high! Next time I rig something to suspend it from) it good, squeezed it by twisting it, and still pretty wet, I put it in another pot.

I used hot tap water which is probably about 104f at the kitchen sink, to sparge. There was still plenty of wet in all that grain, and I added two gallons of water, stirred it in the bag, drained, and squeezed all the goodness out of it. I ended up with about 2.5 gallons there, and almost 6 gallons in the big kettle.

Boiled both, an hour each, an ounce of cascade in each batch. I thought a little extra hops might mask any slight weakness in the recipe caused by overextraction or whatever.

Ended up with about 5.5 gallons in the big pot and a hair over two gallons I think in the small one. Fixing to hook up the chiller coil and cool them down and take a gravity but the big pot wow it is thick and sticky, and the little one is not far behind, so they are going to be fairly sturdy beers, both. And yeah maybe I could have done a third extraction but it is getting late as it is, and I want to get these brews into their Bigmouth Bubblers and pitch the yeast before I go tits up and lights out. Plus I am concerned that maybe a third extraction might not be as pleasing to the palate as most of my beers have been. I don't know. I will try it some day, I guess. So let me go chill that stuff, take readings, get it busy in the bubblers, and catch you all in the morning.

 

[GrowleyMonster]

No, it doesn't. Using hot water can help you create more sugar, if your mash conversion is incomplete when you start sparging, but hot water will not improve lauter efficiency.

Brew on

But wouldn't hot water take up more sugar into solution? Within reason, that is.

 

[GrowleyMonster]

I read the article and the conclusions, I guess we will agree to disagree. I might be wrong but I learned from the old school brewing books and it seems that everything we used to do has been proven wrong or unnecessary. Hopefully the OP still makes his 2nd running beer, I believe he'd be missing out on a nice easy drinker.

Yeah it just seemed like the right thing to do. Lots of sugar in there. Really sticky. Didn't seem right to just toss it, especially since I had plenty of free yeast from the last brew. I will be surprised if the second squeezing is leaner than about 1.06, actually.

 

[GrowleyMonster]

Whew. In the fermenters. I ended up with 5gal with sg1.074 @ 71f, and 2gal at sg1.034 @ 68f. Seems like I should have done slightly better than that but that's okay, still should be one great corny keg full and three sixpacks of "stout lite" LOL. The one pound of chocolate was maybe more than I needed, and I will go half that amount next time unless I really like how it tastes. The spent grain still tastes really sweet and malty.

 

[doug293cz]

But wouldn't hot water take up more sugar into solution? Within reason, that is.

Hot water can hold more sugar in solution, but at mash temp you can dissolve 2 lb of maltose in 1 lb (about 1 pint) of water. With a very thick mash (0.9 qt/lb) you can only create about 0.41 lb of sugar per 1 lb of water, which is only about 20% of the maximum sugar that can be dissolved at mash temp. So, there is plenty of water at mash temp to keep all the sugar created in solution. And, the sugar does not need to be dissolved because it is in solution when it is created. There is never any solid sugar to dissolve.

Brew on

 

[doug293cz]

Whew. In the fermenters. I ended up with 5gal with sg1.074 @ 71f, and 2gal at sg1.034 @ 68f. Seems like I should have done slightly better than that but that's okay, still should be one great corny keg full and three sixpacks of "stout lite" LOL. The one pound of chocolate was maybe more than I needed, and I will go half that amount next time unless I really like how it tastes. The spent grain still tastes really sweet and malty.

These numbers seem to be consistent with the predictions I made in my earlier post. They aren't the same, since my assumed volumes were a little higher than your actual volumes. I'll rerun my simulation with your actual volumes on Monday.

Brew on

 

[Steven_C]

I recently did a bigger stout (9%), and did a porter with the second runnings by just putting the bag in a second vessel with mash-temp water for about 30 minutes, stirring every now and then and squeezing the bag well. The second runnings gave me what would have been 4%, so I added Molasses to get it up to 5%. It was quite good!

 

[GrowleyMonster]

I recently did a bigger stout (9%), and did a porter with the second runnings by just putting the bag in a second vessel with mash-temp water for about 30 minutes, stirring every now and then and squeezing the bag well. The second runnings gave me what would have been 4%, so I added Molasses to get it up to 5%. It was quite good!

Nice. Yeah I could see molasses working pretty good to bring the grav up. Tastes a little bit like LME, anyhow.

So after a slow start, both batches are perking merrily along now, at around 71f internal temp. I got them in front of a window unit in case it gets too warm in the house. I am really looking forward to tasting the big beer especially. I will probably bottle the second squeezings.

 

[GrowleyMonster]

Second squeezings into a keg for conditioning. FG was 1.008. So like 3.4%, two gallons, that would have been wasted. Moochers coming over to drink up all my beer beer LOL! It's going into bottles. I'm gonna try some brown PET bottles and carbo caps, bottling 5 bottles at a time. Might start tomorrow. Anyway in 10 days I need that keg empty for the big batch.

Brewing anotherr batch today. 14.5lb of the Viking 2 row pale, .5lb of the Briess Chocolate 350, and just for the hell of it a pound of oats. So 16lb total grain and 5 gallon keg target. I increased my water to 8 gallons. I think I used 7.5 gallons last time and I barely got my 5 gallons of product. I reduced my strike temp to 155, and ground the grain a bit finer, as fine as the Corona can handle without grinding itself up. The previous batch is going into the secondary while this batch boils so after cooling I will drop it right on top of the trub in the primary.

Once again I am going to do a second run, 3 gallons. I have a 3lb can of pale extract I am thinking about adding. Life is too short for sub 4% beer. So my first runnings will still be all grain but the leavings will not. Looking for a 2 gallon batch again.

Thinking about some L80 caramel for the next batch, cause I think I will like it better than the chocolate. I might up the grain one more pound, maybe with corn masa which I have plenty of because I always plan to make homemade tortillas so I buy dry masa, but I end up not making the tortillas because it is a lot of work. Therefore the corn is actually free because it is left over from making tortillas that never actually got made. GF buys the groceries, anyway. So likewise, the oats are free too haha! I can probably sneak in a pound of flour, too, for that matter, maybe cut the pale malt back by a pound.

Too bad hops don't grow well here in New Orleans. GF loves to grow stuff. She is totally cool with a hops trellis in the front yard. Now if I can just get her to plant some barley... LOL free beer would be way cool.

 

[Jayjay1976]

I like this idea of scavenging a second small beer from the spent grain that would have similar flavor to the first, plus you can always add a pound of DME to boost the gravity if it comes in low.

 

[Kirkwooder]

Second squeezings into a keg for conditioning. FG was 1.008. So like 3.4%, two gallons, that would have been wasted. Moochers coming over to drink up all my beer beer LOL! It's going into bottles. I'm gonna try some brown PET bottles and carbo caps, bottling 5 bottles at a time. Might start tomorrow. Anyway in 10 days I need that keg empty for the big batch.

Brewing anotherr batch today. 14.5lb of the Viking 2 row pale, .5lb of the Briess Chocolate 350, and just for the hell of it a pound of oats. So 16lb total grain and 5 gallon keg target. I increased my water to 8 gallons. I think I used 7.5 gallons last time and I barely got my 5 gallons of product. I reduced my strike temp to 155, and ground the grain a bit finer, as fine as the Corona can handle without grinding itself up. The previous batch is going into the secondary while this batch boils so after cooling I will drop it right on top of the trub in the primary.

Once again I am going to do a second run, 3 gallons. I have a 3lb can of pale extract I am thinking about adding. Life is too short for sub 4% beer. So my first runnings will still be all grain but the leavings will not. Looking for a 2 gallon batch again.

Thinking about some L80 caramel for the next batch, cause I think I will like it better than the chocolate. I might up the grain one more pound, maybe with corn masa which I have plenty of because I always plan to make homemade tortillas so I buy dry masa, but I end up not making the tortillas because it is a lot of work. Therefore the corn is actually free because it is left over from making tortillas that never actually got made. GF buys the groceries, anyway. So likewise, the oats are free too haha! I can probably sneak in a pound of flour, too, for that matter, maybe cut the pale malt back by a pound.

Too bad hops don't grow well here in New Orleans. GF loves to grow stuff. She is totally cool with a hops trellis in the front yard. Now if I can just get her to plant some barley... LOL free beer would be way cool.

I brewed for many years. thinking that bigger beers were the only ones worth brewing, and I still love to brew IIPA's, but I have brewed several small beers lately that have turned out wonderfull. A pint of 4% cream ale kicks ass on a hot summer afternoon of throwing horseshoes, and when you can brew one from your seconds, why not?

 

[InspectorJon]

I like this idea of scavenging a second small beer from the spent grain.

I do this and freeze the second runnings in 1/2 liter soda bottles to use as starter wort. From a 3.5 gallon 1.088 doppelbock batch I got 3/4 gallon of 1.040 second runnings. Could have added a bit more water and small amount of some crystal roast got a gallon batch of something else.

 

[GrowleyMonster]

I do this and freeze the second runnings in 1/2 liter soda bottles to use as starter wort. From a 3.5 gallon 1.088 doppelbock batch I got 3/4 gallon of 1.040 second runnings. Could have added a bit more water and small amount of some crystal roast got a gallon batch of something else.

I didn't know the yeast would survive a freeze. Sounds like a pretty good idea.

 

[Ridenour64]

I didn't know the yeast would survive a freeze. Sounds like a pretty good idea.

I think he means just freeze the wort, then at a later time, thaw, bring to temp, then pitch yeast.

 

[GrowleyMonster]

Brew day results. This was my third BIAB batch and my second batch with the cheap Viking pale as the main grain. Mash bill is already in post 21. I had to do a longer boil because the 8 gallons of mash water left me with almost 7 gallons after pulling the bag and giving it a good drain and squeeze. After the boil I was left with a little over 5-1/2 gallons and after chilling to 70f my OG was 1.073, a little less than I anticipated but still okay. As planned I dumped it into the just used fermenter with the trub from the previous batch still in there. It was working after two hours. Nice. So I had total volume in the BMB of about 5-3/4 gallons.

Second run I confess to a lack of discipline. Didn't measure the water. About 3 gallons, a bit hotter than mashing temp. I put the bag back in the kettle but suspended it above the bottom, and slowly poured the sparge water through it with the kettle spigot open and a smaller kettle catching the product. Sort of like making pourover coffee. Then I did a really hard squeeze and didn't give up until I thought I had everything I was gonna get. Ended up with... drum roll... 3 gallons of second squeezings. I should have stopped there, chilled it, and taken a SG but I poured the mash back into the brew kettle and fired it up. Figuring of course that it would be a little light, I added about a pound and a half of leftover LME that I had opened to cook with, (I made several batches of bread with LME and trub for leavening) and thinking that wasn't enough, I added another pound bag of pilsner DME. And did a 90 minute boil with an ounce of Cascade, ended up with a hair over two gallons. I knew this small beer wouldn't be a teeny tiny small beer but in retrospect even without calculating, I should have expected a pretty good OG due to the low volume. I actually forgot to take the reading before going to the fermenter. I didn't want to open a packet of Safale for this little batch of leavings so I just opened the spigot on the BMB holding the first run, that was already working good, and drew off a quart or so into the BMB for the second run. Finally there I was, close to 2-1/2 gallons and whoa, hey I never took the OG. Imagine my surprise when it was 1.080. Well okay I'll take that. I needed to use the LME before it got stale but I could have saved the DME for fixing another batch. I didn't need the seconds to be so big as I figured it wouldnt taste as good as the firsts, anyway.

So finally I am looking at 8 gallons minus the devil's share left in the trub, at fairly high grav, in primary ferment. I am trying to keep a two keg surplus for the upcoming wedding and it was getting a bit tight... I thought I would have to drink store beer but maybe I am okay if we don't have any guests in the next two weeks. Previous batch seconds is in the fridge crashing, and firsts are in secondary, going to keg in about 10 days. And then this batch coming along right behind, will put me on easy street, inventory wise.

So I was thinking about doing my own malting, to further reduce cost. In retrospect I spent the best part of the day yesterday grinding and lugging stuff around and pouring and stirring and lifting and today I am feeling it. I think the work involved already with pre-malted barley is enough work, and I am getting a fairly big beer for chimp change as it is.

Second run... worth the work? Yeah, to me it is. I think. I will test taste the seconds from the previous batch today. If it doesn't move me, then maybe not, after all. If it does, I will go ahead and fill a few bottles and carb em up. I need to get that keg empty soon.

 

[Soulshine2]

I just ground 14lb of Viking Pale 2-Row and a pound of Briess Chocolate 350 for my second BIAB batch and my biggest beer to date. My first BIAB batch I just tossed the grain after mashing. But this is a bigger batch, and I am wondering if there are enough fermentables left in the mashed grains to get another couple gallons of wort out of them, with reasonable gravity. Honestly I am okay with anything over 4% ABV, if the alternative is to just toss it. A lighter beer can be nice when working in warm weather and this is New Orleans, after all. I am thinking maybe after draining the bag over the kettle, I might give it a soak in a couple gallons of warm water and maybe sparge it a bit before discarding. What say you experienced brewmeisters? Would this be worthwhile?

The reason I am thinking this might be a thing is that with higher gravity wort, more sugars will be left in the grain, and clear water ought to recover a fair amount of that. 15lbs of mashed grains ought to be good for SOMETHING, right? I don't have chickens.

i actually did it once with my first AG brew. It started out as a Hefeweizen in grain bill . the next day I had the same thought as I could still taste sugars in the so called spent grains. How much I was unsure of . So, what I did was resparged the grains to basically a half of my normal batch size of 5 gallons (so I had 2.5 gallons), boiled with different hops and added a pound of dextrose to the boil along with zest of lime and a tiny bit of orange zest and crushed a tsp of coriander . Then cooled as usual and pitched US-05 . What resulted was a really nice session "belgian" i dubbed Moon Over Miami since I used Apollo hops and had the citrus zest in it. Wonderful on a hot day. The water you re-sparge with doesnt necessarily have to be warm , you've already converted the starch to sugar so all you need to do is sparge , cold or cool water will work fine. I would make sure you use 1/4-1/2 a campden tablet .

 

[InspectorJon]

I think he means just freeze the wort, then at a later time, thaw, bring to temp, then pitch yeast.

Yes, freeze the second runnings. You will need to boil it some before using it as starter wort to make sure it is sterile. I do a 10 minute low boil/simmer, let it cool and pitch yeast to make a starter. Free starter wort for not much work.

Do check SG. Starter wort should be typically be 1.030-1.040. Boil longer or add water as necessary to get there.

 

[GrowleyMonster]

i actually did it once with my first AG brew. It started out as a Hefeweizen in grain bill . the next day I had the same thought as I could still taste sugars in the so called spent grains. How much I was unsure of . So, what I did was resparged the grains to basically a half of my normal batch size of 5 gallons (so I had 2.5 gallons), boiled with different hops and added a pound of dextrose to the boil along with zest of lime and a tiny bit of orange zest and crushed a tsp of coriander . Then cooled as usual and pitched US-05 . What resulted was a really nice session "belgian" i dubbed Moon Over Miami since I used Apollo hops and had the citrus zest in it. Wonderful on a hot day. The water you re-sparge with doesnt necessarily have to be warm , you've already converted the starch to sugar so all you need to do is sparge , cold or cool water will work fine. I would make sure you use 1/4-1/2 a campden tablet .

When does the campden tablet go in? In the mash? After boiling? I have never used that, and in fact I had never heard of them. What about bisulfite levels? Am I correct in thinking that they would be inconsequential at that dosage?

 

[Jayjay1976]

What doed everyone think of Viking malt? I picked up 50 lbs of their pale malt and haven't been impressed. I'm trying to use it up to make room in my bins for something else.

 

[GrowleyMonster]

So, here is the latest batch, after 12 hours in the BMB.

 

[odie]

I used some viking recently. Haven’t drunk it yet

 

[Soulshine2]

When does the campden tablet go in? In the mash? After boiling? I have never used that, and in fact I had never heard of them. What about bisulfite levels? Am I correct in thinking that they would be inconsequential at that dosage?

the campden tab goes in my strike water , it removes chlorine from the water. I had a 6 gallon batch go extra bandaidy on me and I ended up dumping it. I was really pissed, it was a Kolsch . after running it past the masses here, it was thought due to chlorine. so , since then I use campden in every batch. How I managed to do it in 10-12 previous batches without that taste is beyond me. Cheap insurance if nothing else.