OG way off. Help! How did I screw it up?

Brewing Processes
1

Hi, i’m still new to All grain brewing. I’m trying to make an IPA with an OG of  1.070. I ended up with an OG of 1.045 instead. I have no idea why i’m so low. I used brewgr.com to calculate my mash/sparge water. Maybe I entered the values wrong? i don’t know. Below is my recipe and the brewer.com calculations. If you more experienced brewers can go over my work and help me locate exactly where i screwed up I’d greatly appreciate it.

Here’s the recipe:

Sierra Nevada Torpedo Extra IPA clone
(5 gallons/19 L, all-grain)
OG = 1.070 FG = 1.018 IBU = 70 SRM = 11 ABV = 7.2%

Ingredients
14 lbs. (6.4 kg) pale malt
11 oz. (0.31 kg) caramel malt (60 °L)
17 AAU Magnum hops (60 mins)(1.2 oz./34 g of 14% alpha acids)
1.0 oz (28 g) Magnum hops (5 mins)
1.0 oz. (28 g) Crystal hops (5 mins)
0.67 oz. (19 g) Magnum hops (dry hop)
0.67 oz. (19 g) Crystal hops (dry hop)
0.67 oz. (19 g) Citra hops (dry hop)
Wyeast 1056 (American Ale), White Labs WLP001 (California Ale) or Fermentis US-05 yeast
1 cup corn sugar (for priming)

Step by Step
Mash at 152 °F (67 °C). Boil for 90 minutes, adding hops at times indicated. Ferment at 68 °F (20 °C). Dry hop for 10 days to 2 weeks or use a torpedo to add hop character.

Here’s the calculations I entered into the spreadsheet:

Grain weight: 14.11 lb
Grain temp: 72F
Total Boil Time: 90 minutes
Wort into Fermenter: 5 gallons
Target mash temperature: 152F
Mash thickness: 1.25 qt/lb

here’s the calculated totals:

Runoff volume: 7.20 gallons
total water needed: 9.46 gallons
mash/strike volume: 4.66 gallons
1st runnings: 2.54 gallons
sparge volume: 4.80 gallons
strike temperature: 164.11

So mashed at 154, I was a tad higher than i should have been, for 60 minutes in 4.66 gallons of water. I fly sparked with 4.8 gallons. I might have sparked a little too quickly. only took 15 minutes if that. I boiled for 90 minutes. I ended up with about 6 gallons of fermentable wort with an OG of 1.045. What happened? Thank you.

2

Two thoughts:

  1. How is your crush? Many efficiency issues are the result of a too-coarse crush on the grain. If you are milling at your homebrew shop, consider running it through twice. If you use your own mill, check the gap, and/or run the grain through twice.

  2. Check your thermometer calibration. During my first all-grain batch, I had a monstrously low efficiency, and discovered (via trial-and-error) that my digital thermometer was 20 degrees too low!

3

Andy, I actually did have problems with my digital thermometer. I thought it was working fine while I was mashing but i noticed it was wildly off when I was heating my sparge water. i ended up using my old brewers best thermometer to finish the day. Could it be that my mash temperature was way too low and I didn’t realize??

4

That’s certainly possible…if you actually mashed too low, that could be one explanation for the low efficiency.

5

If your thermometer was way off, that might be it.  But I’m more inclined to wonder about your sparge procedure and lauter setup.  One thing you could try is batch sparging to see if that improves things.  If it does, then it’s your sparge setup or process.

And of course, grain crush is always my first suspect in loww efficiency.  Crush til you’re scared!

6

One thing I notice is you designed your recipe for 5 gallons but ended up with 6. If you had boiled off that extra gallon your OG would have gone from 1045 to 1054. That is still low, but not as bad as it first appears.  Does your 6 gallon measurement include any trub/wort you discarded? Any discarded wort and trub should be accounted for in efficiency calculations.

Math: 45 gravity points * 6 gallons / 5 gallons = 54 gravity points.

7

I agree with all the above - volumes, crush, and accurate temp measurement may all be playing a part. Also, software is totally inaccurate in estimating OG without entering your efficiency on your system. For example, using someone’s posted recipe in amounts (instead of % ) never takes onto account the efficiency you’re able to attain, therefore your OG could vary considerably.

8

Low conversion could be a
Culprit as well.