Hitting Your OG Numbers

Hello all I wonder if anyone can suggest some tips for me.

I have a Grainfather G30 brewing system and for the past year or so I have been really struggling to hit the target OG. I used all grain kits so I know the target OG for the kit. I have regularly been coming in under but today I brewed a NEIPA and the target OG was 1.065 from a 45 minute mash. I hit 1.045 :frowning: .

My pump is working well but I’m not sure recirculation is working as well,I regularly have to slow the pump down to a trickle to keep the amount of wort sitting on top of the grain bed to a sensible level, I think this is inhibiting my ability to extract sugar.

Any thoughts on what might be going wrong ?

Many Thanks


Dup / deleted

a grain father really is like brew in a bag mashing. The re-circulation will keep your temperature consistent which should help control the fermentability of the wort but as long as you keep the temperature between 140f and 160f you should get your OG. Fermentability is another mater that’s going to affect FG. That is not what you are concerned with so I doubt the re-circulation is the problem unless your temperature is out of that zone. That leaves crush and volume measurement are big ones. Mash Ph can also affect the conversion. So my questions are do you crush your own grain. Also have you adjusted your kit recipe to reflect your own brewing efficiency. You may need to adjust all the kits you buy with DME. We would love to help solve this problem but need more information .

I agree with @brew_cat with crush first and if the kits come with pre crushed or you have your own mill. My simple solution would be to add more base malt. Unless you have to add a large amount, it shouldn’t alter the recipe enough to notice but raise the OG.

Not a sin to add some extract but in an all grain batch I like to keep it AG.

I’d be checking weight, volume of water. Verify mash temps and times…

In addition to the above walk us through your brew process. From start to finish. In regards to your pump- you only need to keep the wort moving to maintain temps while avoiding scorching the wort. When you run your pump too fast you’re compacting your mash bed, which, if you do any sparge will limit extraction.

1 Like

Hello @brew_cat thank you for the thoughts, well I don’t crush my own malt I always buy an AG kit and it’s ready crushed. I’m not sure how to assess my brew house efficiency, can you advise on that ?

Thanks @hd4mark - would adding more malt also mean I need to adjust the water volumes ?

Hi @loopie_beer so I would work as follows - always following the recipe from an AG kit.

  1. Use the GF app to set up the recipe - often I can find it on the app but occasionally I set it up myself
  2. Add water to the brew kettle and get it up to strike temp
  3. Add grain and give it a stir for a few minutes, trying to make sure no lumps etc.
  4. Start the pump and recirculate for 60 mins (depending on the recipe) with a rise to typically 75c for 10 mins
  5. Lift the grain basket and sparge with the app advised volume of hot water usually about 75c
  6. Boil for 60 - 90 mins depending on what’s being brewed add hops and any additions per the recipe
  7. Cool the wort using a cold water driven coil
  8. Transfer to the fermenter
  9. Pitch the yeast

well this is probably the problem. Whoever packaged the recipe kit is using their efficiency. I’ve heard the generally use 70%. So you will need to adjust the recipe if you want to get what they advertise because looks like your getting less. if you record your OG and what they predicted you can probably figure out the difference. What I would do then is use an online recipe builder, input their recipe with your efficiency % inputed in your recipe then adjust. If you go this route you might as well buy ingredients ala carte and save money. There is ways to increase your efficiency but that may be more involved than you want to be. If your off by .01 on all your brews try adding a lb of DME and call it a day,

So a couple things- first is crush. Pre-crushed grains are notorious for poor efficiency as they usually aren’t crushed with a tight gap. Second thing to look at is your sparge. Again, if you recirculate too fast it will compact your grain bed and your sparge water will channel.
So what can you do? First, watch how quickly you recirculate. To help with your sparge you can also rake the mash but be careful not to go too deep and disturb your filter bed.
You can also consider buying a mill and crushing your own. I will say that I’ve found that constant recirculating systems actually work better with a bit of a wider crush, which can also help your sparge.
Lastly, you can do as @brew_cat suggests and build your recipe based on your brewhouse efficiency. Might take a bit more grain, but you’ll hit your target OG.
A thing about brewhouse efficiency- it really doesn’t matter what it is as long as you’re CONSISTENT.

1 Like

I use about 1.5 quarts of water (yes quarts since I haven’t caught up to that metric stuff yet :smile: ) per pound of grain in the mash but there is a little wiggle room depending on the recipe. So unless you are adding a lot of grain I wouldn’t be too concerned.

I bag brew and I have similar issues with OG. My control of mash temp is great. For me, I think PH and crush are likely culprits (I mill at the brew shop). A possible 3rd issue is that maybe Beersmith estimates aren’t that accurate… I use distilled water and add brewing salts to get to profiles and estimated mash PH. I usually end up 0.5% abv below the estimate pretty regularly. Rather than buy a PH meter that I have to pamper, I tend to cheat with 1/2 pound or so of DME if I really want to hit OG.

I do full volume mash in a basket… I stir quite often, constantly recirc, albeit slow… pH is corrected BEFORE the grains go in. My brew house rides at 80% +/- a wee bit. Well, that using .35 ppp. Now I haven’t brewed in a year, but I’ll verify my results soon…

1 Like

If you haven’t brewed in a year you may have to leave :rofl: shame shame shame


With all this you have to very accurate with measurements, especially volume. I doubt pH is your problem. And like you I got rid of my pH meter after confirming that Bru’n water would ALWAYS get me to .01 of target pH. Now when I make sours I simply taste it :joy:
With all that said, if your always .5% low then your consistent.

The guy I introduced brewing too has brought me growlers of his brew, so……. (:

Thanks Loopie. I might give Bru’n water a try since I’ve pretty much just gone with beersmith for all calculations, including ph.

I would look at crush and volume. Again, if it’s ALWAYS that exact amount low then you’re consistent. Simply change your effeciency to match your OG for future recipes.