Missed target OG - how to add DME

[CHSBrewer]

I'm just getting going with BIAB/all grain brewing and am in the process of dialing in my equipment. My first batch I missed volume and OG targets and ended up with 4 gal and 1.054, while my targets were 5 gal @ 1.068. I've seen the equations for calculating how much DME to add to compensate and found the Adjust Gravity tool in BeerSmith, but one thing I can't tell is how to account for the water needed to boil the DME before adding to the fermentor.

Using the BeerSmith tool, if I use the current volume, then it tells me I need to add 1.27 lbs of DME. If I put in 5 gallons since that's my target volume, I need 1.59 lbs. I'm assuming that since I'm adding water with the DME then I need to add that water volume to my current wort volume and dissolve 1.59 lbs in 1 gallon of water. Accounting for the water added with the DME hasn't been spelled out anywhere I've been able to find so I wanted to double-check.

Any help or opinions is greatly appreciated, thanks!

 

[iamwhatiseem]

Forget about adding DME - you need to figure out how you got a lower OG with 1 gallon less wort!!... your efficiencies are extremely low.
List here your brewing steps... particularly mash temp, how long did you mash, what temp was the mash after.
How do you drain the bag, do you squeeze thoroughly, are you rinsing etc.
That or there is an error in your gravity reading.
Cheers!

 

[rburrelli]

Use just enough water to dissolve it. That small amount will be negligible in your overall calculations. The amount BeerSmith is telling you to add should be based upon your batch size. You should not need to recalculate anything.

 

[ike8228]

I don’t mean to to hijack the thread (sorry if I do), but I have a follow up question to the OP. Perhaps this will help them or others and for me. In the event your OG is lower than expected two questions:
1. As long as it is not tooo low, can’t you just boil off some water to bring the ratio down? Less beer, but more accurate numbers.
2. If you were to add more malt/sugars would you bring your wort back up to a boil and add or do it separately and add back, like the OP is asking? I know you can’t take a reading when the wort is still hot? From what I know hydros only work at around 70 degrees.

 

[IslandLizard]

Forget about adding DME - you need to figure out how you got a lower OG with 1 gallon less wort!!... your efficiencies are extremely low.

I wouldn't say to forget about the DME, I would add enough to get 4 gallons at 1.068 (or close to that) but you surely need to get your efficiencies higher and volumes closer to the what BS gives you.

Did you add any top up water that didn't get mixed thoroughly before you took the gravity reading?

A poor crush (too coarse) can play havoc with starch conversion in the mash giving you low gravity (low sugar content). Common problem with pre-crushed malt from online stores and LHBS. But your results seem excessively low to just count for that.
Unless you left a whole bunch of sugars behind somewhere that never made it into your wort.

 

[Silver_Is_Money]

The difference between 68 and 54 is 14 PPG. 4 gallons x 14 PPG = 56 points required. DME has ~43.5 PPG (points per pound per gallon).

56/43.5 = 1.29 Lbs. required to raise the initial 4 gallons to an SG of 1.068.

Then you also need 68/43.5 = 1.56 Lbs. for the additional gallon of water you need to add to end up with 5 gallons.

So the total DME you need to add such that the entire 5 gallons has an SG of 1.068 is 1.29 + 1.56 = 2.85 Lbs.

To assist with your dialing in process, you would have needed to add on the order of ~5 Lbs. more base malt and 1 additional gallon of water to have hit your target of 5 gallons of Wort at an SG of 1.068.

 

[madscientist451]

Having some DME on hand in case you don't hit your numbers is a great idea. but next time, pull a half pint of wort when you have about 10 minutes in the boil and chill it in an ice bath. If the gravity is low, you can add DME at flameout. I really don't like the taste of extract and if it bothers you too, you can add some DME and some sugar or honey or just all sugar.
Lately, I've been doing overnight BIAB mashes and a dunk sparge in the morning in a side pot and I've been consistently hitting my numbers.
Getting your volume squared away is a matter of trial and error and depends on your boil rate and some other factors, just keep good notes and keep making adjustments and you'll figure it out.

 

[Silver_Is_Money]

you could also compute it this way:

4 gal./5 gal. x 54 = 43.2 (meaning that when 1 gallon of water is added to hit 5 gallons your SG drops from 1.054 to 1.0432)

68 - 43.2 = 24.8 gravity points of boost required for each gallon

24.8 gravity points/gallon x 5 gallons = 124 gravity points required for 5 gallons

124 points required per 5 gallons / 43.5 points/gallon for DME = 2.85 Lbs. of DME required for 5 gallons

 

[CHSBrewer]

you could also compute it this way:

4 gal./5 gal. x 54 = 43.2 (meaning that when 1 gallon of water is added to hit 5 gallons your SG drops from 1.054 to 1.0432)

68 - 43.2 = 24.8 gravity points of boost required for each gallon

24.8 gravity points/gallon x 5 gallons = 124 gravity points required for 5 gallons

124 points required per 5 gallons / 43.5 points/gallon for DME = 2.85 Lbs. of DME required for 5 gallons

Thanks for the explanation. I will keep this example so I can figure it out next time (though hopefully there won't be a next time).

This was my first BIAB batch so I don't have accurate measurements on a couple of things I know I need to adjust recipes for my system (pH, boil off rate, trub loss). All I had to go on was defaults this time so my volumes and grain amounts were more or less guesses as I had to start from somewhere. For those curious, I do have some notes and measurements:

- 13# grain crushed at LHBS
- 7 2/3 gal water heated to strike temp of 162.
- Added to igloo cooler lined with BIAB, added grains, stirred to break up clumps
- Measured temp after 5 min @ 153, 65 min @ 148. Target mash temp was 152.
- Pulled bag after 70 minutes total, squeezed and let drain, transferred to kettle to start boil. Lost 1/2 gallon to dead space in mash tun
- pre-boil gravity was 1.042
- 60 minute boil

From what I've found researching, I probably need a longer mash time, and another gallon of water obviously to account for what looks like a pretty rapid boil off rate (2 gallons/hr it seems). Also may ask the LHBS to run the grains through twice, though have seen conflicting reports on whether that is effective or not.

 

[CHSBrewer]

Having some DME on hand in case you don't hit your numbers is a great idea. but next time, pull a half pint of wort when you have about 10 minutes in the boil and chill it in an ice bath. If the gravity is low, you can add DME at flameout. I really don't like the taste of extract and if it bothers you too, you can add some DME and some sugar or honey or just all sugar.
Lately, I've been doing overnight BIAB mashes and a dunk sparge in the morning in a side pot and I've been consistently hitting my numbers.
Getting your volume squared away is a matter of trial and error and depends on your boil rate and some other factors, just keep good notes and keep making adjustments and you'll figure it out.

Thanks for the suggestion to check things with 10 minutes left, I'll remember that for next time.

 

[CHSBrewer]

I don’t mean to to hijack the thread (sorry if I do), but I have a follow up question to the OP. Perhaps this will help them or others and for me. In the event your OG is lower than expected two questions:
1. As long as it is not tooo low, can’t you just boil off some water to bring the ratio down? Less beer, but more accurate numbers.
2. If you were to add more malt/sugars would you bring your wort back up to a boil and add or do it separately and add back, like the OP is asking? I know you can’t take a reading when the wort is still hot? From what I know hydros only work at around 70 degrees.

1. Yes, I could have boiled some more water off to concentrate the wort, but not sure how that would affect the hops utilization. If you use a hop bag or some way of separating the hops that you can just pull out then I don't think that would be an issue. Aside from the whole less beer thing, which just isn't fun
2. I boiled the new water and DME/sugar separately and then cooled it before adding to the fermentor, then pitched the yeast.

 

[Silver_Is_Money]

Thanks for the explanation. I will keep this example so I can figure it out next time (though hopefully there won't be a next time).

Thank you! I generally strive to provide actual answers to peoples questions, in conjunction with showing how I derived the answer(s). To me that seems to be the sole reason as to why this Forum has a category titled Brewing Science.

 

[IslandLizard]

- 13# grain crushed at LHBS
- 7 2/3 gal water heated to strike temp of 162.
- Added to igloo cooler lined with BIAB, added grains, stirred to break up clumps
- Measured temp after 5 min @ 153, 65 min @ 148. Target mash temp was 152.
- Pulled bag after 70 minutes total, squeezed and let drain, transferred to kettle to start boil. Lost 1/2 gallon to dead space in mash tun
- pre-boil gravity was 1.042
- 60 minute boil

7.67 gallons may not be quite enough water for a 5 gallon all grain batch of 1.068. Did you put all those 7.67 gallons in your mash tun? Or save some out?

Not really a BIAB process...
For BIAB, you typically use the bag inside the kettle, and insulate it during the mash period to reduce heat loss. IOW, with BIAB, your boil kettle is your mash tun.
When using a cooler as a mash tun, you need some other sort of filter to separate the grist from the wort. Such as a bazooka tube, a false bottom, or in your case, a BIAB bag would be fine too.

So, since you used a bag inside the cooler, the bag IS your filter. After pulling and squeezing/dripping the bag, the wort left in the cooler should be fairly clear and free of grain bits. Dead space is immaterial here, all the wort in the cooler should have ended up in the kettle.

Now if there's indeed 1/2 gallon of "dead space," where water accumulates without touching the grain, it surely doesn't help your mash efficiency.

Given the low volume you got 1.042 preboil is pretty poor for 13# of grain. Sounds like that grain was not crushed finely enough.

 

[CHSBrewer]

All of the water went into the mash tun, so adding more water next time is on the list, especially due to the apparent high boil off rate.

And I know I'm doing BIAB slightly different in using a converted cooler, I wanted to go ahead and get the cooler with the intent of later moving to "true" all grain. Even though I have a pretty tightly woven bag, I'm still left with cloudy wort at the bottom after I drain it out, and the first bit of wort that I drain into the kettle is also somewhat cloudy though it clears quickly. Not sure what, if anything, that means.

I will ask at the LHBS about the gap on the rollers and if they can run it through twice next time. That seems to come up often here and in other articles.

I haven't bothered with testing my mash pH and no one has really brought that up yet. Is that something I should worry about at this point? Or add more water and check the grain crush first?

 

[IslandLizard]

All of the water went into the mash tun, so adding more water next time is on the list, especially due to the apparent high boil off rate.

And I know I'm doing BIAB slightly different in using a converted cooler, I wanted to go ahead and get the cooler with the intent of later moving to "true" all grain. Even though I have a pretty tightly woven bag, I'm still left with cloudy wort at the bottom after I drain it out, and the first bit of wort that I drain into the kettle is also somewhat cloudy though it clears quickly. Not sure what, if anything, that means.

I will ask at the LHBS about the gap on the rollers and if they can run it through twice next time. That seems to come up often here and in other articles.

I haven't bothered with testing my mash pH and no one has really brought that up yet. Is that something I should worry about at this point? Or add more water and check the grain crush first?

With a high boil off rate you should have gotten a much higher gravity. Once you start boiling, gravity and volume is like a rubber band.
Any clue how much you boiled off. 2 gallons? If so, turn that heat source down, a good simmer is plenty, better even than a full rolling boil. No need for wild splashing and potential boil overs.

1 gallon boil off is sort of an average target for 5 gallon batches, but depends on a few variables, sure.

Why does your mash tun have such a large dead space?
That's not good. Maybe it can be reduced?
If that's what you're aiming for to use in the future that needs to be addressed.
But... There's really nothing wrong with BIAB in your kettle. Many brewers are very successful using that method and won't even consider anything else, they literally swear by it.

Also, BIAB with finer milled grist can get you very high mash efficiency, 80-85% is fairly common. Some get 90% with lower gravity brews.

Cloudy wort is not necessarily detrimental. Unless it's a crazy amount. It should all precipitate, but yeah, better to avoid putting it all in the kettle, in the first place.

You could try to pour the cloudier part of the wort through your grain bag hung inside or over a (large) bucket. The wet grain itself is the filter we normally use when doing a vorlauf in regular mashing.

Definitely take a close look at the crush. Something is way off. There should be no grain piece larger than 3/32" in diameter. With BIAB it can be even finer, containing some powder even, since the bag is a very fine filter.

Any clue what your water is like? If municipal, you need to remove the chlorine or chloramines. You can call them and ask for the mineral it contains. Their quality control dept. has the data.
The pH of your water is meaningless, the minerals it contains, and the derived alkalinity, are important, especially in the mash.

 

[IslandLizard]

with the intent of later moving to "true" all grain.

BIAB is true all grain. It only uses a different mash technique, often full volume mashes, although some incorporate a sparge. But you can't do LoDO with it, which is in a different ballpark.

 

[CHSBrewer]

Interesting about the boiling intensity, had always heard that a rolling boil was better but obvioulsy that would increase the boil off rate. Decreasing the heat is certainly easy, and along with checking the crush on the grains and maybe asking for a finer crush from the LHBS then I might be able to make some improvements pretty easy. Thanks for the analysis everyone!

Water quality report from the city:
Chloramine, mg/L 2.1
pH, standard units (range) 7.4–7.5
Alkalinity, mg/L 24
Calcium, mg/L 5.1
Chloride, mg/L 11.0
Conductivity, micromhos/cm 204
Hardness - Calculated, mg/L 22
Hardness - EDTA, mg/L 23
Orthophosphate, mg/L (as PO4) 1.17
Potassium, mg/L 2.20
Sodium, mg/L 26.7
Sulfate, mg/L 44.5
Total Solids, mg/L 113
Zinc, mg/L 0.33

I think I've got pretty good water but it looks like hardness (if I assume calculated == "as CaCo3") is low. Will have to confirm that with public works and ask about carbonate, bicarbonate, and magnesium levels. It looks like those 3 are not on the report and are of interest to brewing.

 

[Silver_Is_Money]

If your hardness is 22 ppm (mg/L), and your calcium is 5.1 ppm, then your magnesium must be 2.23 ppm.

If your alkalinity is 24 ppm, then your bicarbonate is 29.3 ppm.

At pH 7.4 to pH 7.5 you don't have any appreciable carbonate. Right close to all of your alkalinity is bicarbonate.

 

[IslandLizard]

checking the crush on the grains and maybe asking for a finer crush from the LHBS

A proper crush is usually the first and main step to better efficiency.
Most LHBS won't change their gap. But if theirs is totally off, they might.
And milling wheat or rye on those is usually a total waste of ingredients. Like in that blind tasting "wheat beer" someone had brewed, me scoring it at 13 (the grace score) and asking where's the wheat? Ouch!

Milling twice on a gap that's too wide won't make for a better crush than once, with the correct gap.

For example, I reset my mill at least once for every brew session. I use a 0.034" gap for barley, and 0.025" for small kernel grain such as wheat, rye, and flaked goods (yeah, I mill those). For oat malt and crystal oats (Golden Naked Oats) I go another notch tighter. It gets roundout scary when milling triticale, millet and such, the knurls are almost touching, and still need to run it through twice or more.

In short, if you're serious about brewing, getting your own mill is no luxury. And a sack of base malt. You can brew any day.