Consistently Low Pre/Post Boil OG

If there's one thing that has been consistent in my all-grain batches, its my consistently low OG. Recently I've been adding DME after checking the Pre-Boil gravity, to off-set the gravity, but the last time I tried that my OG ended up WAY over. I know there's a million posts on efficiency, and I've read many of them, so after doing much of my own testing and evaluation, I figured I'd break down and ask for some help. Here is what I've troubleshooted so far:

Crush - I use a maltmill, and always seem to get a great crush out of it. Whether we hand crank it, or use the power drill, always seems to break it up well, everything ends up in small chunks and has a nice powdery topping.

Temperature - At one point my thermometer went WAY off, so I thought just getting a few more therm's would fix the problem. It helped, and I know my mashes hold good temp, but still didn't fix it completely.

Mash/Batch Sparging - This is one thing I've been trying to get down. I'm pretty good at getting the right amount out for my full boil, but my method has always been: Strike with water at temp to bring mash to 150-154, stir good and let sit for an hour or so(1.25-1.5qt/Lb Grain-whatever beersmith says to do). Now by the time I do my 1st runnings my temp is in the mid to high 140s, and I completely drain the tun. THEN I add around 180 (split sparges) stir and run off. Now I've been reading about adding this sparge water BEFORE draining, and bringing the whole mash temp up THEN draining. Would this help? I especially use the previous method, because I was doing 10g batches with a 10g mash tun. But with my 5gal batches, maybe I could try the latter method. (Sometimes I feel like I go against the grain with beersmith's mash settings. I changed it to *drain mash tun, but then I like to split the sparge up-one of the settings creates multiple sparges, but then I can't change the temp of them individually)

Boil Off - This is another area that I'm trying to nail down, because sometimes I use a big turkey fryer pot, sometimes I use the keggle for 10 gal batches. Of course the keggle is harder to obtain/keep a good boil, thus seems to boil off less. I had a vigorous boil in the turkey fryer on this last batch.

MLT Dead Space - Again another area that may be affecting my efficiency. My drain is several inches off the bottom, with slots on the top. Seems like I have quite a bit of deadspace in there(but even when I account for a gallon of deadspace, I still seem to miss)

(I haven't been checking the gravity on every running, but if that would help, what would I be looking for to ensure consistency? Also I have run the iodine test before, and its never failed, but I always allow plenty of time to convert. I have never checked the water quality in my area, but St Louis/St Charles has pretty good water.)

Here is the info from my last brew:

13.3lb grain
Strike with 4g of water @ 152(grain temp) - maybe should have been 5 because of MLT deadspace?
DRAINED roughly 2 gallons.
Sparged 2 gal @ 180 - Ran off 2 gal
Sparged 2.5 gal @ 180 - Ran off 2.5
Total of 6.5 g full kettle

Estimated Pre-Boil 1.058
Actual Pre-Boil OG: 1.044
(Added 2 lb DME towards the end of the boil to compensate)
Estimated Post-Boil 1.067
Actual Post Boil OG: 1.074
Boiled for 80 minutes
End Volume into Carboy - 5 gallons

I'm wondering if maybe instead of adding the DME, I should have just boiled off longer? If that's the case though, how long would I boil if my pre-boil gravity is low?

Looking back at this last brew, I didn't make the equipment adjustments, except choosing the 7.5g brewpot(I used my turkey fryer kettle for this 5g batch)/10g cooler MLT. The settings were only .25g lauter/tun deadspace...but even when I put in 1g with my full keggle specs, I seem to still consistently come out low.

I thought I found a crutch by adding the DME, but it seems that may not be the best route, and I really want to nail this down.

By the way, this was for a BIG IPA that I wanted to brew up to drink for my bday at the end of October. I'm calling it A Hoppy Birthday Ale The IBUs are about 80, so its not a bad thing my OG came in a little high. I threw in another 2oz of dry hops and tasted a sample yesterday...its delicious, already down to 1.012. I thought it may come out too bitter, but I combined FWH with 80min hops, and lots of aroma hops, and it seems to have blended nicely. Can't wait to keg it up

The good thing with homebrewing is no matter what the OG/FG, the end result still usually produces a damn good beer

Sorry for the long post, but I'd certainly appreciate any feedback or suggestions you all may have. Thanks again!

Why did your mash temp drop 10 degrees over your mash period? That doesn't sound right.

When I dough in my ~164F/1.5L per pound strike water, my mash temp after 2-3 minutes is about 154F. In my setup, I have my MLT insulated so I stay +/- 0.5F over the 60 minutes.

From what I know, it's important to keep it as close to 154F over the 60 minutes (assuming your doing a 60min mash) as possible. You're extraction capability changes at the different temperatures.

Something may be wrong with your equipment/process if you're dropping roughly 10 degrees over the hour. Did you preheat the MLT?

Yes I preheated the MLT. There is an opening at the front of it(where you open it) I wonder if that is letting some heat out. It may have been in the high 140s, closer to 150, but it definitely looked like it dropped a little bit (I just yanked it out and checked, so I wasn't incredibly thorough with the post-mash temp). Maybe I need to try and seal the front, or throw something around it to insulate it more.

What's your mill gap? What's you water source like (ph perhaps)? And are you using malt conditioning methods at all?

Also, yes 10 degrees drop is very significant IMO.

In the Maximizing Efficiency thread the consensus seems to be around .7 mil. Use an automotive feeler gauge to get this dead on. If you're not malt conditioning, try it

Learned a lot from this one:

https://www.homebrewtalk.com/f36/maximizing-efficiency-when-batch-sparging-77125/

My guess is even a few degree temperature drop is a red flag. I have never tried the malt conditioning, and honestly never heard of it until now. Wikipedia had some good info on it. I never changed the factory setting on my maltmill. I'll grab a feeler gauge and check that out. Thanks for the great info so far guys!

My mill is set to about .040mil, so I don't think crush is the issue. Any other ideas? Even if my temp drops in the mash to 148, would that put my efficiency that far off? Shouldn't I still be getting a good conversion during that time, just with the possibility of being a bit dryer?

Are you checking your OG and ajusting that for temp? If you check you OG at a temp of 130 it can be off by 10+ on your reading, then when it cools and you check it again it's alot higher.

That is something I've been recently doing (previously I would just allow it to cool down at room temp), but yeah I actually cooled down the samples on my last brew. Thanks for the suggestion though. Not long ago, I hadn't realized how big of a diff the temp made on the reading.

I am suspicious of your mashtun. Is it a cooler or some other type of vessel? Have you run tests with just water to see how much is actually left behind? Do you have any pictures of it? I don't have technical data to back it up with, but leaving behinds quantities of sweet sweet wort (especially 1st runnings) cannot help things.

Also if you are compensating for the deadspace in the mashtun, you need to just increase your overall batch size and scale the grain/ingredients with it, not just add additional water to the tun.

The other thing I would do is stick to one brew kettle until you figure out what is going on. To minimize variables.

What do you have the efficiency set to in beersmith? If you consistently low, just lower the number in beersmith to match your system and then add grain to your recipes to make up the gravity you want.

If your consistently getting 65% then you really don't have a problem. If it's under 60% then maybe you should work to improve the efficiency but have an consistent number is more important then having a high number.

I think you could crush finer. I set my mill to .35 and have no problems lautering.

My MLT is a converted 48qt cooler with a copper false bottom that sits well off the bottom of the cooler and has slots on the top(def some deadspace in there). I usually set my eff to 70%, in hopes that I will get a higher eff. I think I usually hit closer to 60, so maybe I should set it for that, and if I set the MLT deadspace to 1g in beersmith, will it compensate for grains as well as water? The way you made it sound, I have to actually increase the batch size also??

chapa said:

My MLT is a converted 48qt cooler with a copper false bottom that sits well off the bottom of the cooler and has slots on the top(def some deadspace in there). I usually set my eff to 70%, in hopes that I will get a higher eff. I think I usually hit closer to 60, so maybe I should set it for that, and if I set the MLT deadspace to 1g in beersmith, will it compensate for grains as well as water? The way you made it sound, I have to actually increase the batch size also??

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yeah set beer smith to 60% and readjust your recipes. You will be using a few more dollars in grain but try not to let that bother you. 60% is not fantastic but as long as it's consistent your one step ahead of the game. I'm not sure why efficiency always turns into a penis size contest.

Dead space is not all the area under the false bottom. It's the liquid that won't drain out because the spigot is too high. Anything you can do to more fully drain the cooler and reduce that dead space will increase your efficiency. You could probably reduce the dead space by simply tilting the cooler towards the drain. Does that make sense?

I just tested it, and it leaves just under a gallon under the false bottom, that won't drain. I don't always incline the cooler when draining, so I'll def do that from now on. I could also re-solder the false bottom to make the slots on the bottom, but I don't know how great of an idea that is.

Any deadspace in the system (mashtun, kettle, chiller, etc) you will be losing beer/wort.

On my setup, I usually lose about a .25 gallon of liquid in the kettle due to trub and hop matter. So i have to build that into the recipe. I like to end up with about 5.5 gallons of beer in bottles/keg so I just set the batch for 6 gallons. Lose ~.25 on brewday due to deadspace/trub and then probably another .1-.25 in the fermenter due to yeast cake/trub. this could probably be improved, but for my current setup, it works well.

So if I find a recipe for 5 gallons, I input that into pro-mash and scale it up a gallon which then scales the ingredients up. If you just scale your water amount up, without scaling the grains, then you will just be diluting your recipe and undershoot your OG. I have no idea how to do this in beersmith, as I don't use that program, but I know lots of people here use it and can probably chime in.

Also if you have a copper manifold you usually want the slots/cuts in the copper facing down.

chapa said:

I just tested it, and it leaves just under a gallon under the false bottom, that won't drain. I don't always incline the cooler when draining, so I'll def do that from now on. I could also re-solder the false bottom to make the slots on the bottom, but I don't know how great of an idea that is.

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What you have is a pipe manifold? That's much different then a false bottom. With a pipe manifold you'd want the slots to face down to reduce the dead space.

ian-atx said:

So if I find a recipe for 5 gallons, I input that into pro-mash and scale it up a gallon which then scales the ingredients up. If you just scale your water amount up, without scaling the grains, then you will just be diluting your recipe and undershoot your OG. I have no idea how to do this in beersmith, as I don't use that program, but I know lots of people here use it and can probably chime in.

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Beersmith has a very user friendly scaling tool as well.

You're right, its a copper manifold, not a false bottom. Well looks like I have some soldering to do. So let's say I turn the slots towards the bottom, and get it down to 1/2 gallon left over in my MLT. Just input that as the deadspace in beersmith, set my boil rate to 1g/hour and set my efficiency for 60%(hopefully will end up a little higher with making these adjustments). Do I need to increase my batch size also? Seems like these factors would make the adjustments for me.

chapa said:

You're right, its a copper manifold, not a false bottom. Well looks like I have some soldering to do. So let's say I turn the slots towards the bottom, and get it down to 1/2 gallon left over in my MLT. Just input that as the deadspace in beersmith, set my boil rate to 1g/hour and set my efficiency for 60%(hopefully will end up a little higher with making these adjustments). Do I need to increase my batch size also? Seems like these factors would make the adjustments for me.

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You need to figure your boil off rate with some trial and error. Everybody's is somewhat different.

You only need to change your batch size if you want more or less wort at the end of boil. Personally, I aim for 6 gallons at the end of boil. With trub and hops loss, I get 5.5 gallons into the fermenter. Following the ferment, I'm able to siphon off a full 5 gallon keg of clear beer. My recipes are designed to produce a 5 gallon keg of finished beer. You design your recipes for whatever volume you want.

If you don't want to do all that soldering, you can always use a stainless steel braid (water supply hose) instead of the copper manifold. I personally like the steel braid better b/c I get great eff. (75%), it is easy to clean, easy to store (its so little compared to a pipe manifold), and only cost about $3.

Here is my mash tun setup

I feel like the copper manifold would minimize stuck sparges, just because the slots are bigger. Is that not the case? I have a steel braid on the my keggle, and can never get the wort to drain out of the kettle without it getting clogged. I assume the trub is a little tougher to drain through than the mash. I think the guy I bought the keggle from was using it for a MLT.

I have never had a stuck sparge with my steel braid. If you are have problems with that, then something else is wrong in your brew process (maybe too fine of crush?). But I don't think you are having that problem anyways.

Stuck sparges should only be a concern when the wheat in the mash gets >40%, which can be counteracted by adding 1 lb of rice hulls to give that mash some structure!

Chapa - I think your mash eff. problems is mostly your temp. drop during mash (that is a no-no) and slightly less important is your left over wort in the MLT.

chapa said:

I feel like the copper manifold would minimize stuck sparges, just because the slots are bigger. Is that not the case? I have a steel braid on the my keggle, and can never get the wort to drain out of the kettle without it getting clogged. I assume the trub is a little tougher to drain through than the mash. I think the guy I bought the keggle from was using it for a MLT.

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In the mash the husks in the grain bed provide the filtering. The manifold is there to distribute the flow more evenly and avoid channeling. Channeling is not a concern for batch sparging so you can easily get away with using a braid.

Also, you should remove the braid from your keggle. If it gets stuck when your ready to drain out the wort, it's much more trouble then it's worth.

maida7 said:

Also, you should remove the braid from your keggle. If it gets stuck when your ready to drain out the wort, it's much more trouble then it's worth.

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So should I actually drain the finished wort from the keggle, and just not use the steel braid? Otherwise, I figure if i take it off, I wouldn't be draining anyway...

funkswing said:

Chapa - I think your mash eff. problems is mostly your temp. drop during mash (that is a no-no) and slightly less important is your left over wort in the MLT.

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I'll have to really check that better next time, and make sure its holding the temp. I always seem to remember it holding temp ok, but still losing a few degrees of heat after sitting.

Even if it is not holding heat very well, would a few degrees really make a huge diff on efficiency? I would assume as long as I stayed above like 148, it would still convert OK...which leads me to believe the left over water that is never accounted for in the MLT would be my main concern. Maybe I should hook up the steel braid and shoot for a 60%, and see if I magically hit 70+% for the first time While I'm at it, I should probably still try to seal the lid opening a little more, and make sure that it holds the heat better.

What do you guys think about that temperature though? Would losing a few degrees throw my efficiency off THAT much?

bump...thanks for all of the feedback. I am planning to remove the copper manifold and replace with a steel braid. Based on losing 1 gallon of sweet wort after mashing for 1hr(under the manifold), combined with possibly losing a few degrees during the mash(any suggestions for insulating the cooler further??), does this sound like it will bring my efficiency up quite a bit?

Should I go ahead and shoot for a 70% efficiency again, or just set it to 60%, and just hope to hit a little higher(showing that the methods were effective)?

Chapa - set it for the 60%, and just be happy if you get better (have some additional hops on hand in case you want to boost your IBUs b/c of the higher OG).

Can you post a pic of your MLT? I think we are confused by you saying "I need to seal the lid better to avoid heat loss". Are you using a cooler? Are you using a keggle? What are you using (sorry if you already answered this question)?

As for after your boil, I would just drain the wort into the fermenter (chilled, of course) and take out that stainless braid from the boil kettle. I guess it was there to filter hops? But I could see it getting clogged pretty quickly with all your break/hop material.

There are a bunch of posts on how to setup a boil keggle (find ones with pics). I would read up on those. I personally autosiphon out of my boil kettle b/c I don't have a valve installed, so I can't help you there.

funkswing said:

Chapa - set it for the 60%, and just be happy if you get better (have some additional hops on hand in case you want to boost your IBUs b/c of the higher OG).

Can you post a pic of your MLT? I think we are confused by you saying "I need to seal the lid better to avoid heat loss". Are you using a cooler? Are you using a keggle? What are you using (sorry if you already answered this question)?

As for after your boil, I would just drain the wort into the fermenter (chilled, of course) and take out that stainless braid from the boil kettle. I guess it was there to filter hops? But I could see it getting clogged pretty quickly with all your break/hop material.

There are a bunch of posts on how to setup a boil keggle (find ones with pics). I would read up on those. I personally autosiphon out of my boil kettle b/c I don't have a valve installed, so I can't help you there.

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Ditto!

I'd add that if you find a increase in efficiency and overshoot your gravity it's very easy to add some water to the boil to bring it back down.

Here is my MLT, a 48qt cooler with a ball valve installed to a copper manifold. It's hard to see on this pic, but there is a slight gap in the front of the lid, where cooler lip and the lid meet. Its not a huge opening, but its there. One time I tried taping the front opening with a wide painters tape. Surely duct tape would work better. My only concern with doing the steel braid, and correct me if I'm wrong, if the outlet for the drain is still at the same height as the manifold, even if I put a steel braid in its place, won't my placement of the drain still have an effect on the gravity of the drain? I assume I would NEED to lift the one side of the cooler, to make sure it all reached the height of the drain(which would likely still work better with the steel braid)





(Regarding the KEGGLE that has the steel braid/drain)
I typically use a siphon to transfer from kettle to fermenter, but tried using the drain at one point(just to try it) and it got clogged very easy at the steel braid...HOWEVER I believe the previous owner of my keggle was using it as a MLT. I think the trub from a boil may be too dense to drain through a steel braid, where as with the husks in a mash will filter much better.

chapa said:

My only concern with doing the steel braid, and correct me if I'm wrong, if the outlet for the drain is still at the same height as the manifold, even if I put a steel braid in its place, won't my placement of the drain still have an effect on the gravity of the drain? I assume I would NEED to lift the one side of the cooler, to make sure it all reached the height of the drain(which would likely still work better with the steel braid)

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Use an elbow or some tubing to lower the braid to the floor of the cooler.

AND/OR

Tip the cooler toward the drain when doing your runoff.

I can't see the opening in the lid, but if it is there, would placing something heavy on top of the lip help? Like a dictionary or some lifting weights? Also, you could put a blanket over whole cooler after you mix in the grains to help with the heat.

Another idea is to pre-heat your cooler with your strike water. Usually ppl with coolers don't need to do this (unless your cooler is stored someplace where it is cold before mashing, like a cold basement/garage), and usually only ppl that use metal MLT pre-heat it. After pre-heating, you either re-heat the water to the strike temp (if needed) or you can just over heat your strike water, pre-heat the MLT, then lower the heat via ice cubes and stirring (but doing that sucks). You really just have to calibrate your own equipment.

Also, most ppl tend to put something under the cooler to make it slant to drain out most of the wort; that is perfectly fine to do. You will never get all of the wort out.

Chapa, just turn your existing copper manifold over, the holes should face down. You are losing too much wort to the large dead space.

next time you mash, just put a blanket or sleeping bag over your cooler, put something heavy on top of it and you will hold temps much better.

with those two things, go ahead and brew another, I bet you raise your efficiency by at least 10 points.

try it, and post back.

funkswing said:

you can just over heat your strike water, pre-heat the MLT, then lower the heat via ice cubes and stirring (but doing that sucks). You really just have to calibrate your own equipment.

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I find this method works very well. I put in my strike water extra hot. Give the cooler some time to absorb the extra heat. Then dough in and use a few ice cubes if necessary to bring it down to the proper temp. With this method I loose very little temp during the mash.

With out pre-heating the cooler I would loose 5 or more degrees during the mash

Phatuna's response is a good idea too, but ultimately, if you are batch sparging the copper manifold is a waste of space. Since you already have that steel braid, it shouldn't be too much of a hassle to switch it over to your cooler. If you ever want to start fly sparging, keep that copper manifold around.

Also, looks like you would have to cut and re-solder that manifold to make it fit upside-down.

maida7 said:

Use an elbow or some tubing to lower the braid to the floor of the cooler.

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Wouldn't gravity still be a factor? Even if I got the braid to lay on the floor of my cooler, it seems like the amount that it had to raise up from the braid to the drain would still restrict the drainage...but maybe I'm wrong. I suppose as long as the actual DRAIN HOSE ended up below the cooler it would still work...

funkswing said:

I can't see the opening in the lid, but if it is there, would placing something heavy on top of the lip help? Like a dictionary or some lifting weights? Also, you could put a blanket over whole cooler after you mix in the grains to help with the heat.

Another idea is to pre-heat your cooler with your strike water. Usually ppl with coolers don't need to do this (unless your cooler is stored someplace where it is cold before mashing, like a cold basement/garage), and usually only ppl that use metal MLT pre-heat it. After pre-heating, you either re-heat the water to the strike temp (if needed) or you can just over heat your strike water, pre-heat the MLT, then lower the heat via ice cubes and stirring (but doing that sucks). You really just have to calibrate your own equipment.

Also, most ppl tend to put something under the cooler to make it slant to drain out most of the wort; that is perfectly fine to do. You will never get all of the wort out.

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Putting a weight on top may actually help, and to be safe I could still maybe throw a little duct tape on the front and a blanket over the top.

I do always pre-heat my mash tun, previously I would just add part of my strike water for a few minutes, and then throw the grains on top and immediately top off with the rest of the strike water. Then I was reading some people who drained the water after pre-heating(which I guess just rids the potentially gross water that sat at the bottom(doubt it really matters), but the problem with that is it will create inconsistencies in the strike water volume) so last time I just heated a small separate pot of near boiling water, and used that to pre-heat, then just drained and added the grains/proper volume of strike water.

chapa said:

Wouldn't gravity still be a factor? Even if I got the braid to lay on the floor of my cooler, it seems like the amount that it had to raise up from the braid to the drain would still restrict the drainage...but maybe I'm wrong. I suppose as long as the actual DRAIN HOSE ended up below the cooler it would still work...

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If you can create a siphon effect it will drain the space below the level of the spigot.