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Low OG

How can I have brewhouse efficiencies in the 80’s and end up with a low OG?
I start my boil with 7 gallons of wort, and usually end up with 5 - 5.5 gallons
in the fermenter. by the time I bottle I’m down to 44 - 45 bottles.
Whats making my OG low. ( its never real low, just usually a few points off.

Thanks for any help,

OG would be the gravity reading of the wort just prior to adding yeast.

The number of bottles you fill has no bearing on the OG.

What is the recipe and what gravity reading are you getting before adding the yeast?

If you are just a few points off, I would attribute it to being off on your water volumes. I believe it is impossible for anyone to be able to emphatically say that they have X gallons pre boil and Y gallon in the fermenter. You are going to be within a pint/quart. Enough to be off a point or two.

For the big evaporation rate, you may try a less vigorous boil. I typically lose a gallon an hour with the boil.

The low OG happens fairly regular. I measure with a gratuated pitcher as the wort exits the mash tun, so my preboil volumes are pretty close.
The amount that I bottle reflects the amount lost to the boil, for this example it was 2.5 gallons.

The last brew I did was this:
8lbs pale 2 row
8oz crystal 60
8oz roasted barly.
Mashed in at 153 for 90 minutes
90 minute boil.
Pre boil volume = 7.5 gallons at gravity of 1.040, temp 70*
OG after boil = 1.054, target was 1.060.

I figured my max PPG at 47.36, which means my efficiency should be above 84%

I know a few points don’t mean a whole lot,. but I’ve been trying to improve my consistincy and refine my system.

You need a couple more lbs of 2 row to hit your numbers.

HBS crush? Double crush it.

Crushed at home? Tighten the mill down a little more.

Crush til you are scared. :wink:

How do you measure the amount going into the fermenter?

Got it on the extra malt. When the recipies are made, are they based on an efficiency of 100% ?
I have been double crushing lately, which probably helped on my efficiency. I haven’t had any stuck runoffs yet.

I don’t measure what goes in the fermenter. I had one marked at on time, but the ones I use now are’nt marked, yet.

One other question, Do you guys ever add water to the fermenter if you boiled off too much? I tried it once and came up with a bad beer, so now I just live with a little less, but better beer.

I think they are based on 70 or 75 % efficiency.

I have added water before but only when my OG was way to high I never worry about being short I just go with what I have.

[quote=“daled”]Got it on the extra malt. When the recipies are made, are they based on an efficiency of 100% ?
I have been double crushing lately, which probably helped on my efficiency. I haven’t had any stuck runoffs yet.

I don’t measure what goes in the fermenter. I had one marked at on time, but the ones I use now are’nt marked, yet.

One other question, Do you guys ever add water to the fermenter if you boiled off too much? I tried it once and came up with a bad beer, so now I just live with a little less, but better beer.[/quote]

If you don’t know how much is going into the fermenter, your efficiency is an educated guess. note: I don’t measure mine either, I boil down to the OG I want.

[quote=“daled”]The low OG happens fairly regular. I measure with a gratuated pitcher as the wort exits the mash tun, so my preboil volumes are pretty close.
The amount that I bottle reflects the amount lost to the boil, for this example it was 2.5 gallons.

[/quote]

The 2.5 gallons also would include the amount left behind in the fermenter. It may be less than a pint, but it still contributes to the error factor.

[quote=“Nighthawk”]HBS crush? Double crush it.

Crushed at home? Tighten the mill down a little more.

Crush til you are scared. :wink:

How do you measure the amount going into the fermenter?[/quote]

Did a stout recently that used to go 1.052 with one run through the mill. This time I milled it twice and got 1.061. I’m going to tighten the gap first chance I get.

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