Low OG, anyway to salvage?

[j_strzempka]

I'm new to all grain brewing and just did my 4th batch. I did an Oatmeal Stout recipe that I got from Northern Brewer website. OG was suppose to be 1.042 but mine ended up at 1.028. I'm thinking it was because it was the first dark beer I have done and I should have mashed a little longer to convert sugars.
Is there anything I can do to salvage this batch?
Or do I have to just suck it up and know it will probably finish at 2% ABV after fermentation?
Any hints or suggestions with dark beers in the future would be helpful!

Thanks!!

 

[northernlad]

When doing AG always take a preboil gravity. This will tell you whether you have reached you target or you have to add some extract.

ex: Target OG 1.042@5g= 42X5= 210 gravity points
gravity points/preboil gravity = 210/6.5=32
These numbers are constant. If your preboil gravity is lower than expected adjust accordingly with DME/LME

These and other neat tricks can be found in Designing Great Beers. (and you thought you'd never use math after high school)

 

[Gremlyn]

I would invest in a refractometer. It allows near instantaneous measurement of gravity so you know where you are for your numbers. As for the current beer, if you're already fermenting, it's pretty much too late. Call it a breakfast stout...

 

[Frodo]

I'm thinking it was because it was the first dark beer I have done and I should have mashed a little longer to convert sugars.
Is there anything I can do to salvage this batch?
Or do I have to just suck it up and know it will probably finish at 2% ABV after fermentation?
Any hints or suggestions with dark beers in the future would be helpful!

Thanks!!

Darker malts convert just as quickly as pale malts if there is starch to convert and you have the enzymes from pale malt to convert it. Many of the darker malts only require steeping to extract or dissolve the sugars/flavors and that happens pretty quickly. If you used the same mash/sparge process but got a much lower efficiency, I'd be willing to bet your grains weren't crushed well enough.

If you're really concerned about the low OG of the batch and you just put it in the fermenter, and fermentation hasn't started yet, you could probably boil some DME in a bit of water and add it - just an idea that would probably work.

 

[biochemedic]

What's wrong with adding DME after fermentation is started...or even finished for that matter?! I often do late additions of fermentables if I'm using something like brown sugar, molasses, or honey.

Oh, and perhaps your reading was off due to layering or incomplete mixing?

 

[biochemedic]

What's wrong with adding DME after fermentation is started...or even finished for that matter?! I often do late additions of fermentables if I'm using something like brown sugar, molasses, or honey.

Oh, and perhaps your reading was off due to layering or incomplete mixing?

 

[knotquiteawake]

When doing AG always take a preboil gravity. This will tell you whether you have reached you target or you have to add some extract.

ex: Target OG 1.042@5g= 42X5= 210 gravity points
gravity points/preboil gravity = 210/6.5=32
These numbers are constant. If your preboil gravity is lower than expected adjust accordingly with DME/LME

These and other neat tricks can be found in Designing Great Beers. (and you thought you'd never use math after high school)

This blows my mind right now. I wish I had known this a couple times in the past. I am stilling trying to lock down my mini mash and keep getting slightly lower than desired (but improving) OGs. I shoulda thought of this.
However I'm not sure how that would work with partial boil.

 

[ian-atx]

Usually technique and process are the best ways to improve brewing rather than buying more stuff, but man, a refractometer for the pre boil measurements when all grain brewing is the way to go. Hell, I would say pre-ferment measurements, although I always get a hydro reading right before I pitch just to make sure all matches up.

You can usually get a decent enough refractometer on ebay for 20-30 bucks.

 

[j_strzempka]

Thanks for the info guys. Will check into a refractometer for sure. And the math makes sense too! Not familiar with DME/LME, will look into that as well!

 

[biochemedic]

DME = DRY malt extract
LME = LIQUID malt extract

 

[funkswing]

northernlad - nice little trick. I have DGB, but I slack and use Promash for all my math. You could also assume ~10 gravity points are gained in a 1 hour boil, less with higher gravity beers and more with lower gravity beers. At least, that works for me.

I don't think you need a refractometer; to keep things simple, when you are taking a pre-boil gravity, just add 20 SG points to your reading to get pre-boil (rough estimate). Ex., pre-boil gravity is 1.028 @ ~155 F, the corrected value is ~1.048. After a 60 min boil, you would have ~1.058 beer.

But you want to know how to fix this right now (and I would, b/c that OG is pathetic!). Do the conc. DME in water. Boil it up for 10 min, cool it and pitch it ASAP into the fermenter. You might get another lag time, but it should work out fine.

I would say you could add like 1 pound of DME and be fine.

 

[Gremlyn]

Adding DME to already fermented beer in any big way may lead to off flavours. I can't promise it will, I've never tried, but I wouldn't be surprised. The yeasties are likely already going dormant from gorging themselves through the original fermentation. You also have to contend with hop utilisation, adding the extra wort so that you don't aerate, etc. Personally I'd chalk this batch up to a goof, drink it anyway (I'm sure it'll be fine) and move on to the next one.

 

[j_strzempka]

Thanks again! I think I won't mess with it and see how it turns out. It's been in fermenter for 4 days now and pretty active. It smells great though. I like the breakfast stout idea!! Thanks for all the info, all of this will help big time on the next batch. Anyone know what white rice solids are for? I got them in a package deal from a guy on craigslist. All he told me was they boost ABV. Anyone have experience with these?

 

[Frodo]

What's wrong with adding DME after fermentation is started...or even finished for that matter?!

Maybe nothing. I was thinking about the possibility of introducing oxygen into the beer after fermentation has started which would oxidize the beer. I can't think of anything else to be too concerned about.

 

[northernlad]

northernlad - nice little trick. I have DGB, but I slack and use Promash for all my math. You could also assume ~10 gravity points are gained in a 1 hour boil, less with higher gravity beers and more with lower gravity beers. At least, that works for me.

I don't think you need a refractometer; to keep things simple, when you are taking a pre-boil gravity, just add 20 SG points to your reading to get pre-boil (rough estimate). Ex., pre-boil gravity is 1.028 @ ~155 F, the corrected value is ~1.048. After a 60 min boil, you would have ~1.058 beer.

But you want to know how to fix this right now (and I would, b/c that OG is pathetic!). Do the conc. DME in water. Boil it up for 10 min, cool it and pitch it ASAP into the fermenter. You might get another lag time, but it should work out fine.

I would say you could add like 1 pound of DME and be fine.

I built my first AG beer from scratch with DGB. I decided on a style, gravity, and IBU and did the figures the old fashined way. This IPA was exactly what I was looking for the first time. I recommend buying Designing Great Beers and getting all up in it. It really helps with understanding what the hel is going on.

 

[funkswing]

I don't think oxidizing the beer would a problem when adding boiled dme to the the fermenter. If you add it nice and slowly, there will be minimal oxygen pick-up (plus, the freshly boiled wort won't have any oxygen in it).

But if its past high kraeusen you prolly shouldn't do it. Just my guess tho.

 

[TJ_Brew]

Is it safe to assume that if you have a low OG, and you have not pitched the yeast, you can easily correct this by adding LME/DME until you get the OG you want?

 

[funkswing]

TJ - of course it is. Its just wort until you pitch the yeast. You can dilute it or concentrate it all you want (the further you go from the OG, post-boil, the more noticeable it may become).

Remember to boil the malt extract for at least 10 min and cool it before pitching it into the fermenter.

 

[TJ_Brew]

Thanks Funkswing. I have been brewing for several years now and this is the first time I have had this issue. I'm glad I'm not the only one. Wish I knew how I screwed up so bad.

 

[viking73]

I just did this to my Rye PA. Had to boil up a batch of DME and add it the next day! Smelled great at bottling, I'll be trying it this coming weekend.

 

[Philsc]

When doing AG always take a preboil gravity. This will tell you whether you have reached you target or you have to add some extract.

ex: Target OG 1.042@5g= 42X5= 210 gravity points
gravity points/preboil gravity = 210/6.5=32
These numbers are constant. If your preboil gravity is lower than expected adjust accordingly with DME/LME

These and other neat tricks can be found in Designing Great Beers. (and you thought you'd never use math after high school)

Yeah, I was good at art and English at school. This numbers lark makes no sense to me.

 

[funkswing]

Philsc - that's why you just get brewing software to make your computer work for you, because after all that's why we created them. Then you can spend more time drawing and drinking beer!

 

[Frodo]

Philsc - that's why you just get brewing software to make your computer work for you, because after all that's why we created them. Then you can spend more time drawing and drinking beer!

I used to be smart but then I learned how to use computer...

 

[msmylie]

I have a related issue that deals with similar situation. I did an Irish red ale that was supposed to have an OG of 1.04...unfortunately it ended up with an OG of 1.03. This was brewed on 11/05 and I did a reading today and got a gravity of 1.01. I am thinking that this beer is finished fermenting. I tasted the sample and it had good flavor, nicely hopped, but it tasted light as hell. It almost has no body to it. Very disapointed with the results. Was wondering if I could rack into a second fermenter with the addition of honey for some further fermentation? Or could I do a concentrated DME or LME boil and rack on top of that? I'd love to save this beer, don't know if there is any way to though.
mfs

 

[Mateo]

Adding DME to already fermented beer in any big way may lead to off flavours. I can't promise it will, I've never tried, but I wouldn't be surprised. The yeasties are likely already going dormant from gorging themselves through the original fermentation. You also have to contend with hop utilisation, adding the extra wort so that you don't aerate, etc. Personally I'd chalk this batch up to a goof, drink it anyway (I'm sure it'll be fine) and move on to the next one.

I just want to point out that this is an unfounded statement. This is practiced extensively in commercial brewing.

There is absolutely no problem adding boiled and cooled liquor (DME + Water) to an active fermentation

I hate to point out blatantly wrong statements but the absolute opposite of what you said is true. In commercial breweries in Germany the blending of batches is done to reduce esters produced in Kolsch beers. A batch is started yeast pitched and several batches are subsequently added to the first batch stepping it up over the course of several days effectively reducing ester production.

You can add wort to you beer, before fermentation, during and after and you will not have a problem so long as its not infected and cooled.

I have done this to correct gravity, to blend, and to condition beers with excellent results.

m.

 

[msmylie]

That is excellent news...any ideas on what type of DME or LME would complement this Irish Red? For a five gallon batch what would be an ideal amount of cooled wort to add? I'm thinking a pound of the same LME used in the original recipe should do the trick, but not sure how much water would be necessary? There is only so much space in the fermenter.
mfs

 

[Mateo]

You will have to use what you can according to head space in the fermentor. There was just a great post on this and it explained it all out.

I have a spread sheet, but its at work and I do not have the formulas off the top of my head.

But is should be something like this:

40 points for the DME (I am guessing here not real sure)

If your recipe called for an OG of 1.048 and you are at 1.028 you need to bump up 20.

40 x 2.5 = 100/5 = 20 points

but you are adding a half gallon so you need:

40 x 3 = 120/5.5 = 21 points.

Not real sure on the math as my brain is shot for today and I could be wrong, but it looks like at a half gallon just over 2.5lbs of DME should do it.

At this point I would just use Light DME. It will diminish the overall flavor profile of the beer a bit, but at least you will have a drinkable beer.

 

[Frodo]

Total Gravity Units = Gravity units x Volume

The gravity units is the whole number after the "1." in the specific gravity; for example, if the SG is 1.030 the gravity units is 30.

So for your irish red with current OG of 1.030 and wanting an OG of 1.040:

First, you can figure out how many gravity units you currently have, assuming you have 5 gallons:

30 GU/gal x 5 gallons = 150 GU

The number of GU you would like to have, for an OG of 1.040, would be:

40 GU/gal x 5.25 gallons = 210 GU (assuming you'll be adding a total of another 1/4 gallon to the fermenter after boiling the DME/LME in the absolute minimal amount of water)

That's a difference of 60 GU.

So you'd need 60 more GU, and in only a total of 1/4 gallon added to the fermenter. 1 lb of DME will supply 45 GU. 1 lb of LME will supply 38 GU. Better to use DME since you have limited space to add to your fermenter. So how many lbs DME?

60 GU needed/45 GU per lb DME = 1.3 lb DME, added to enough water to make 1/4 gallon total.


If you used LME instead:

60 GU needed/38 GU per lb LME = 1.6 lb LME, added to enough water to make 1/4 gallon total.

Those calculations are dependent on you having 5 gallons currently. You can plug whatever volume you do have in the equations, but if you're near 5 gallons it'd end up being close.

 

[msmylie]

This is great information guys. Thanks for the quick responses. One other question I have is with the yeast, do I need to repitch with the addition of more wort? Or, do I need to agitate the yeast cake currently in the fermenter? I assuming there is little to no oxygen in suspension as well...will aerating the new wort be sufficient to provide what the yeast needs? Lots of questions I know, but hate to lose this batch.
mfs

 

[Mateo]

You do not need to repitch and I would avoid aerating the wort.

There is more than ample yeast in the fermenter if you see active fermentation and a good yeast cake on the bottom.. Slightly rousing the yeast to get them in suspension if they have flocculated is a good idea, but do it gently.

Remember the phases of yeast life cycle. O2 is used for reproduction and you are past that phase. You are now in to producing alcohol. So do not aerate.