Bigger beer, smaller starting gravity

[WDT]

I've now got 9 all grain batches brewed and i've missed my target
gravity on all my big beers (1.070+). I'm always about 5-10 points low. Smaller beers are fine, i've calculated around 75% and as high as 77% using my batch sparging method. I want to brew some more complex recipes and I don't feel like bumping up just the base malts on these are a good idea.

Calculator used:
http://www.brewersfriend.com/brewhouse-efficiency/

My technique:

1. I preheat my mashtun (10G rubbermaid seat-top) with about a half gallon of boiling water.

2. Heat my strike water to about 10-15*F above my target temp.
At first I calculated my strike water out at 1.25qt/lb of grain but now I just split the water in half and i've seen no difference in efficiency.

3. Dough in, hand pouring the grain while stirring aggressively with a large whisk as to avoid dough balls.

4. Stabilize my temps and let rest for 1 hour.




For example I brewed Yooper's Ruination twice:

14lbs 2-row
1lb Crystal 20L

First time:
Mashed with 4 Gallons @ 152F for 1 hour, batch sparged with 4.5 Gallons at 170F for 20min netting me 7 Gallons pre boil. Boiled to 5.25 Gallons. Measured 1.070 (target for recipe is 1.077)

Second time:
I added 0.5lbs 2 row (14.5lbs) and mashed with 5.5G/sparged with 3.5G. Measured 1.072.



What's going on here? Is there a trick to mashing a bigger beer? Can you help a frustrated brewer out?

 

[JordanThomas]

With larger grain bills, you will get worse efficiency. It's pretty much always the case. I'd just suggest adjusting your efficiency in your brewing software (I use Brew Pal on iPhone and it rocks... $2). I think I got about 80-85% on probably 4 of my first 5 batches, and about 67% on my breakfast stout clone, which was 20+ lbs of grain.

 

[billl]

There is no real trick. Physics/Chemistry are just working against you as the gravity increases.The higher the concentration of the wort in the kettle, the higher the sugar levels left in the grains and the more sugar lost to your various inefficiencies.

The ways around that are to just plug in a slightly lower efficiency when you are designing "big" beers (which means you will add more grain) OR sparge with more water and just boil longer. You'll only be talking about a dollar or 2 to get up to your intended levels.

 

[inhousebrew]

I use a 10 gallon rubbermaid cooler as well and have noticed a dip in efficiency with bigger beers as well. With small bitters and such I can get around 80%, normal sized beers somewhere from 75-80% and then it drops off for bigger beers. I've gotten as low as 60% brewhouse efficiency for giant beers.

I've just started adding more to big beers to account for it. Aiming low and if I go over that's fine by me. Stir it really good to begin the mash to make sure you don't have any dough balls and then stir the crap out of it when batch sparging to try and rinse those grains really well. Also vaurlof a bunch to set the grain bed and I'd run off slower to decrease the likelihood of creating channels. Most importantly to me is always having a bit of DME on hand just in case. It's not really necessary but if you miss and want to hit your numbers you can always add some.

 

[WDT]

Would you increase all grains including specialty grains proportionally?

I'm planning on a Green Flash WCIPA clone and the recipe is:

14lb (2-row)
1.31lbs (21oz) Crystal 40
1.31lbs (21oz) Carapils

I am not using any brewing software, but I can do the math and bump it up to where I want to be to hit my target of 1.069 based on past experiences.

 

[JordanThomas]

Maybe try using a higher water-grain ratio. Or, just up everything by about 10%. If you want to hit your numbers, you can always top off with water when you are done boiling if you end up high (and you will get more beer this way). Or, boil longer to hit your numbers if you ended low. I usually just roll with what I get, and hope the flavor is on.

 

[billl]

IMO - scaling up the base malt works better than scaling up everything - especially crystal.

 

[WDT]

Any harm in mashing half the grains at a time? Letting the wort sit for an hour and a half.

 

[ludomonster]

You can also add extract to hit your OG. I won't tell anyone.

 

[billl]

"Any harm in mashing half the grains at a time? Letting the wort sit for an hour and a half."

No real harm, but no benefit either. The problem isn't in the conversion of sugars, its in the extraction. You are basically trying to wash sugar out with sugar water. The more sugary the water, the less efficient it will be in washing out the remaining sugar from the grains. It's kinda like mopping a floor with a dirty bucket of water. You are just going to leave some dirt behind that way.

Honestly, your efficiency is fine. If you are getting 75% on regular beers and 70% on big beers, those are solid numbers. If you are just looking to improve your overall efficiency, there are several threads full of great info on that. You are likely always going to have a gap for your big beers though, so just plan accordingly.

Presumably it is typo, but you have 9.5 gallons of sparge listed. You should be shooting for somewhere around 50% of the total volume collected. If you are way off of that, you might try loosening up the mash a little bit by using more strike water.

 

[WDT]

"Any harm in mashing half the grains at a time? Letting the wort sit for an hour and a half."

No real harm, but no benefit either. The problem isn't in the conversion of sugars, its in the extraction. You are basically trying to wash sugar out with sugar water. The more sugary the water, the less efficient it will be in washing out the remaining sugar from the grains. It's kinda like mopping a floor with a dirty bucket of water. You are just going to leave some dirt behind that way.

Honestly, your efficiency is fine. If you are getting 75% on regular beers and 70% on big beers, those are solid numbers. If you are just looking to improve your overall efficiency, there are several threads full of great info on that. You are likely always going to have a gap for your big beers though, so just plan accordingly.

Presumably it is typo, but you have 9.5 gallons of sparge listed. You should be shooting for somewhere around 50% of the total volume collected. If you are way off of that, you might try loosening up the mash a little bit by using more strike water.

Fixed the water volume in my initial post.

I'm getting more like 60-62% efficiency when I calculate it out. Which is why i'm concerned.