Followed All-grain recipe, low OG. reasons for?

[RynoSmail]

So I've seen a bunch of threads on how to fix a low OG. But I want to know WHY it happens so I don't do it again.

I made the Polaris IPA clone recipe from Ballast Point and mashed at 152 for about 45min before the temp dropped to 151 for the next 15-20. (full 60min mash)
11lbs Pale 2-row
1lb Cara Foam
.5lb Cara Vienne
1.25lbs. Crystal 10L
and 1oz. Amarillo whole hops

I came out with a 1.054 OG and it finished with a 1.012 FG. This is not dramatically low but it is a little over 1%ABV less then my goal. I was wondering if I need a different target temp or maybe a step mash? Any suggestions?

 

[JuanMoore]

As long as your temps are within the range the enzymes work at (which they were), they have little to no effect on efficiency. The difference between your efficiency and the recipe efficiency is most likely the crush of your grains, your sparge process, or both. Without any info about your process, it's impossible to say though.

Everyones system and process will result in a different efficiency, so you're going to need to brew a few batches to figure out what YOUR efficiency is, and then adjust recipes accordingly to hit the OG. If your process results in an efficiency that's lower than you'd like, that's a whole other discussion. The key isn't having a high efficiency, but rather having a consistent efficiency, because then you can hit any OG you want easily. What efficiency was the recipe based on? What was the expected OG?

 

[RynoSmail]

Awesome answer Mr. Moore. Thanks for that. As far the crush goes I'm just having the brew shop crush at purchase. I think it does have to do with my sparge. I heated 5.5Gal of sparge water to 170 and and rained a pitcher at a time through a colander. (its my DIY solution until I buy a sparge arm). What I do worry about is I think I used too much. When I reached my target 6.5gal in the brewpot there was still some liquid in the mash tun.
Would having water left over in the tun mean the final sugars weren't pulled through? That maybe that last 1%abv worth of sugars were left floating in the tun?

 

[JuanMoore]

Sounds like you're attempting a fly sparge, in which case water left behind shoudn't hurt any, IF the fly sparge was properly performed. It sounds like you didn't do a mash out, which will hurt your efficiency greatly when fly sparging. People also have a tendency to sparge way too fast when new to fly sparging. It should take at least 45 min to fly sparge. You might consider looking into batch sparging. It doesn't require a mash out, and is much faster and more forgiving than fly sparging. Good luck!

 

[CTownBrewer]

If you think about it, any liquid left in your mash tun has fermentable sugars in it that aren't making it into your boil kettle. I had the same issue on my first all-grain.

In the future, try not to leave any liquid in your mash tun after your sparge. Your grain absorption rate may be off. If you make an adjustment & still end up with extra liquid, just adjust your boil time to compensate for the extra liquid. If you know your boil-off rate, you'll be fine. It may only mean boiling 6.75 gallons for an extra half hour or so to hit your post-boil target. This assumes you have a large enough kettle to handle a larger volume without boiling over.

I've found low OGs on my all-grain brews are due to a combination of crush, mash time (I do 90 minute mashes now), mash temp, & amount of grain in the mash. I request the grain to be crushed a little finer than the normal LHBS setting. Plus, if i'm doing a high gravity beer, I try to add a little more base malt to the grain bill to compensate for the loss in efficiency.

 

[JuanMoore]

If you think about it, any liquid left in your mash tun has fermentable sugars in it that aren't making it into your boil kettle. I had the same issue on my first all-grain.

In the future, try not to leave any liquid in your mash tun after your sparge. Your grain absorption rate may be off. If you make an adjustment & still end up with extra liquid, just adjust your boil time to compensate for the extra liquid. If you know your boil-off rate, you'll be fine. It may only mean boiling 6.75 gallons for an extra half hour or so to hit your post-boil target. This assumes you have a large enough kettle to handle a larger volume without boiling over.

I've found low OGs on my all-grain brews are due to a combination of crush, mash time (I do 90 minute mashes now), mash temp, & amount of grain in the mash. I request the grain to be crushed a little finer than the normal LHBS setting. Plus, if i'm doing a high gravity beer, I try to add a little more base malt to the grain bill to compensate for the loss in efficiency.

A lot of fly spargers keep the liquid above the grain bed for the entire sparge. I agree that he left sugars behind, but not because he didn't collect a large enough volume of runnings. He could have collected 10 gal and still left sugars behind if the process wasn't correct. And collecting more runnings than you need and then boiling forever is a really poor way to compensate for low efficiency, and it's usually cheaper and easier to just add some DME if you find your pre boil SG to be lower than expected, and doesn't risk tannin extraction.

 

[Walker]

It sounds like you didn't do a mash out, which will hurt your efficiency greatly when fly sparging

I am not seeing how a mash out would affect efficiency.

 

[JuanMoore]

I am not seeing how a mash out would affect efficiency.

Only for fly sparging. When fly sparging you're relying on the long slow soak to pull the sugars into solution, which happens more readily at higher temperatures. By raising the temperature of the entire grist before starting the sparge, more sugars dissolve into the sparge water, and lauter efficiency increases. If you have a spoon covered in honey, the hotter the cup of water you place it in, the more honey will dissolve into the water. And adding 170F sparge water to the grist slowly is going to do very little to raise the temp of the mash.

FWIW it's the agitation from stirring that dissolves the sugars into solution for batch sparging, which happens just as readily at just about any temperature, so mashing out has no effect on efficiency for batch sparging. Just like how you could dissolve a lot of honey from the spoon even in room temp water, if you could stir it vigorously.

 

[Walker]

I'll buy that reasoning. Thanks.