Low OG - Help Determine Problem

I'll start by saying that I took the OG without having to add water. My hydrometer reads at 70 and I took the temp at 65. Now onto the recipe, etc.

It is my 3rd batch and I tried Orfy's Mild Mannered Ale, altering it for a 2 gallon batch.
It calls for the following grain bill (parenthesis are what I changed it to):

5lbs 8 oz Maris Otter (2 lb) LHBS was out of Otter and gave me something els but I can't remember what it was. Sorry.

1 lb 8 oz Crystal 60L (.6 lb)
6 oz Chocolate malt (1.2 oz)

Mash at 158 degrees for 60 minutes at a 1.25:1 ratio(I did 3 1/3 quarts). (I have a hard time with mash temps as I do it on a stovetop and was probably 5-8 degrees below the whole time but I did mash for 15 minutes longer)
This left me with 2 quarts of wort, so I sparged with 8 1/2 quarts to reach a preboil of 10 1/2 quarts. I went a little over 20% extra as in my previous 2 batches I came up a little short. This backfired though as I ended up with a 1/2 quart extra.)

One other thing I could see is that in my boil I didn't keep the boil high enough that I didn't evaporate enough of the water off. But I really have no idea if this can be a problem.

The original gravity was supposed to be 1.035 and I came up with 1.025. Anybody have any ideas as to what I did wrong. Thanks a lot.

The extra .5 quart would only drop your OG by about 3 points.
(35 expected final gravity point) * (2 gallons) = 70 points per gallon
(70 points per gallon) / (2.125 gallons) = 33 gravity points = FG of 1.033

In the future, you can just boil longer, but you need to be able to see the volume in your kettle before stopping the boil. Some people carve notches into a stirring spoon to mark off the gallons.

Your problem was with the mash/sparge. Looks like you got somewhere around 24% efficiency. There could be a number of reasons for this. Have you checked or calibrated your thermometer recently?

Sardoman said:

The extra .5 quart would only drop your OG by about 3 points.
(35 expected final gravity point) * (2 gallons) = 70 points per gallon
(70 points per gallon) / (2.125 gallons) = 33 gravity points = FG of 1.033

In the future, you can just boil longer, but you need to be able to see the volume in your kettle before stopping the boil. Some people carve notches into a stirring spoon to mark off the gallons.

Your problem was with the mash/sparge. Looks like you got somewhere around 24% efficiency. There could be a number of reasons for this. Have you checked or calibrated your thermometer recently?

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Thanks for the quick response. I really just need a new thermometer. Right now I'm using a candy thermometer. Also, I really have struggled to keep the temp where I want it in the mash. My first batch was way too high and since then, in my other two, when I found a fairly constant temp that was lower than what the recipe called for, as long as I was reasonably close, then I just kept it there and mashed for a longer time period than what was called for.

Also, I figured up that I had 57% efficiency, where am I off.

2 lbs of Gambrius ESB Pale = 38x2=76 points
.6 lbs of Crystal 60L = 34x.6=20.4 points
1.2 oz of Chocolate Malt = 28x.075=2 points
which totals 98.5 points. So 98.5/2.25 (I was able to keep the extra 1/2 quart because I had room in my fermenter)=43.77. Then 25/43.77=57%

Is this correct? Again, thanks.

You're right, mostly. I was reading 1.2 lbs of chocolate, rather than oz. Also, not knowing what your base malt was, I was assuming 35ppg for it, just to be conservative.

I ran the numbers again and am getting ~55%, which is perfectly fine. BTW, a half quart is 0.125gal, which probably accounts for the small difference between our most recent calculations.

I wouldn't worry about that number being too low. It's consistency that you need. I do partial mashes with a grain bag in a ss pot, and I get 50% eff. every time. Never fails. It's not a problem for me because I know what my efficiency will be and I plan ahead by using a little more base grain to get to my desired OG.

Once you get a reliable digital thermometer and get some consistency in your efficiency readings you will be able to hit your target OG no problem. I would have been concerned about waste at 25%, but around 50% isn't bad. After all, we're talking about small amounts of grain to make up the difference between 50% and 70%.

Sardoman said:

You're right, mostly. I was reading 1.2 lbs of chocolate, rather than oz. Also, not knowing what your base malt was, I was assuming 35ppg for it, just to be conservative.

I ran the numbers again and am getting ~55%, which is perfectly fine. BTW, a half quart is 0.125gal, which probably accounts for the small difference between our most recent calculations.

I wouldn't worry about that number being too low. It's consistency that you need. I do partial mashes with a grain bag in a ss pot, and I get 50% eff. every time. Never fails. It's not a problem for me because I know what my efficiency will be and I plan ahead by using a little more base grain to get to my desired OG.

Once you get a reliable digital thermometer and get some consistency in your efficiency readings you will be able to hit your target OG no problem. I would have been concerned about waste at 25%, but around 50% isn't bad. After all, we're talking about small amounts of grain to make up the difference between 50% and 70%.

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Thanks again. Just as an update, I put the batch into 2 one gallon (actually 4 liter) jugs. They were quick rise and falls. No krausen and little bubbling when I went to bed and when I woke up the krausen had already fallen. But I kind of expected this. Strangely enough, only one of the airlocks is bubbling, even though both are bubbling. So I must have a leak somewhere.

I don't really care too much about the low ABV, I'm not looking to get drunk, I just hope the taste isn't too affected by the low ABV and specific gravity.

BenedictusDeus said:

I don't really care too much about the low ABV, I'm not looking to get drunk, I just hope the taste isn't too affected by the low ABV and specific gravity.

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it should taste just fine, albeit a bit lighter than you planned.

FWIW, i've found that the smaller mashes are a lot harder to hold temp in. what i like to do with any BIAB/stovetop type mash is start with a slightly low water/grist ratio, around just over a qt/lb of grain. i keep a small pan of pre boiled, near boiling water, and a jug of pre boiled, cooled water to adjust mash temps as needed. i'm careful not to add too much water, as to keep the water/grist ratio appropriate. after about 20 or so mins, a lot of the conversion will be complete and temp isn't as much of a worry as long as it's close.
hope that helps in future mashes.

NordeastBrewer77 said:

it should taste just fine, albeit a bit lighter than you planned.

FWIW, i've found that the smaller mashes are a lot harder to hold temp in. what i like to do with any BIAB/stovetop type mash is start with a slightly low water/grist ratio, around just over a qt/lb of grain. i keep a small pan of pre boiled, near boiling water, and a jug of pre boiled, cooled water to adjust mash temps as needed. i'm careful not to add too much water, as to keep the water/grist ratio appropriate. after about 20 or so mins, a lot of the conversion will be complete and temp isn't as much of a worry as long as it's close.
hope that helps in future mashes.

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Great, thanks for the advice.

Last quick update and then I think I'm done. My hydrometer is off. I set it in filtered water and it sinks about (what i can figure) .006 farther than 1.000. I had gotten water in it (there's a hole on the top of it) when I was sanitizing it. Maybe this threw it off? So if this is the case, that helps me out quite a bit by moving my OG up to the 1.030-1.031 range. Still short of the called for 1.035 but much closer.