Actual gravity low compared to est. gravity

[Danger_D]

Hey, so I'm on my 5th batch of beer and I brewed an IPA yesterday. My hopes were to bump up tho ABV on this batch of beer. I entered all my ingredients and info into "brew log" an iPhone app. The app said I had an estimated gravity of 1.081 which seems good. But after the boil I had an actual gravity of 1.060. This seems like a substantial difference and lower than I had hope. Any reason for the difference? It is a 5gal batch and I boiled in a 7.5 gal pot:
Carmel malt 2l- 16oz
Munich malt- 16oz
Light extract- 9lbs

Hops- pellet
2oz Willamette
2oz Centennial
2oz Columbus

Yeast wlp 001

Any tips would be great. One thing that I see controversy on is boil time and temp. Could this affect the actual gravity that much. Would love some tips on your time and temp for a batch like this. Thanks!

 

[beergolf]

With extract it is almost impossible to miss OG unless you volumes were way off. 9 lbs of DME should get you right about what our estimate was.

What volume did you end up with after the boil?

 

[Danger_D]

Thanks for the reply, It was 1.060, so that is 0.021 less than was was estimated. I just got my hydrometer out of the box. Does that need to be calibrated in any way?

 

[Danger_D]

Sorry I miss read your question, the volume was 5 gal exactly. I started with around 6 and lost some to evaporation and left the trub at the bottom

 

[tooldudetool]

DME is around 45 points per pound per gallon. LME is around 37 points per pound per gallon. You didn't specify LME or DME, but 9# x 37 points = 333 / 5 gallons = 66.6 or 1.066 OG. 9# of DME would yield a 1.081 OG. My guess is that you used DME for the calculations, then used LME in your recipe. Is that what happened? You could expect a point or two from the crystal malt, but Munich needs to be mashed to extract any sugars, so there really isn't any point in using it in an extract recipe. The only way you won't get the correct gravity in an extract recipe is if your finishing volume isn't the same as its supposed to be, or it is also possible your wort wasn't fully mixed when you took your hydrometer sample, that is a common problem...

 

[Danger_D]

Ahhh a great observation which is what I am guessing what happen. When I say I used "light malt extract". I say that because the homebrew supply store either sells "light, wheat, or Amber" extract. I didn't know there were multiple malt extracts like DME and LME. So like I said i am an armature at home brewing, but have been a quality beer lover my whole life. I'm on my 5th batch and am addicted. Can you critique my brew:
Steeped my grains at 165 for 30 min
Added all my malt extract and let sit for 30 min at 170
Than added 2oz Columbus 60min
1oz of Williamette at 15
1oz of Williamette 5 min
Irish moss at 15
Yeast nutrient at 10
Gonna dry hop 2oz centennial at secondary ferm

It's only my 5th batch so I know I'm probably over stepping my bounds not following a recipe.

 

[Danger_D]

When you say "wort wasn't completely mixed" I'm not sure what that is (forgive the armature). I used a 7.5 gallon pot so didn't add any additional water. I let my wort cool and let all that nasty stuff settle to the bottom, I have to come to know/call this nasty stuff "trub". When I pour my wort into the fermenter, I leave that trub at the bottom of my pot and do not put it in the fermenter. This is when I took my gravity reading.

 

[tooldudetool]

Typically the wort not being mixed is a problem with partial boils, where people are brewing 3 gallons or so then topping off with cold water to get to their 5 gallons in the fermenter. You should not have that issue with full volume boils, I'm sure the issue was DME vs LME in your calculations.

There are a couple things I see with your recipe. Why are you letting the wort sit for 30 minutes after adding the malt extract? This isn't necessary. I'm a big fan of trying to cut my brew day down to the shortest time possible ( I have a wife and 2 kids so trying to get several hours to myself isn't easy). You really just want to steep the grains for 20-30 minutes at 155-160 degrees, if you go over 170 you risk extracting tannins, so usually you want to steep a good amount below that just in case. Pull your grain bag after 20-30 minutes, add your extract, mix thoroughly, then go straight to heating up to a boil, no need to wait. Once you hit your boil add your bittering hops etc... One thing you may notice with this batch is that it will be very bitter, even for an IPA, because 2 ounces of Columbus should give you over 130 IBU's!! This will make it especially bitter since your original gravity was so much lower than you expected. Since you are building your own recipes I highly recommend using some brewing software, I use Brewtarget, which is free. It lets you pick a style and gives you the basic parameters for IBUs, ABV, etc, so you know if you are in the ballpark. Then you can also see what moving hop additions and amounts around will give you for IBU's, and you can see what gravity you will get from different extract additions. Also I recommend checking a chart to make sure that you are using steeping grains that don't need to be mashed, such as this: https://www.homebrewtalk.com/wiki/index.php/Malts_Chart

One other thing, make sure you are oxygenating your wort before pitching your yeast, either by pouring it into the fermenter from high up to encourage splashing, pouring it through a sanitized strainer, or shaking the crap out of the fermenter to mix the air in the headspace in. Search the forums for other methods, but this is a key step to making sure your yeast attenuate the beer fully.

Good luck and welcome to the wonderful world of homebrewing!!

 

[ktblunden]

Ahhh a great observation which is what I am guessing what happen. When I say I used "light malt extract". I say that because the homebrew supply store either sells "light, wheat, or Amber" extract. I didn't know there were multiple malt extracts like DME and LME.

DME is Dry Malt Extract, LME is Liquid Malt Extract. DME has a higher potential gravity because there is no dilution of liquid. As was mentioned, if the recipe was calculated using DME and you used LME you will have a lower gravity.

 

[Danger_D]

Thanks a lot for the detailed answers. Some great info!!!

 

[Shred]

You can generally expect 20% less fermentables from LME than DME due to water content. Also, while your IBUs may be higher than expected, you won't get to 130. There comes a point (typically around 80-90 IBUs) where the software is no longer accurate and IBUs become anyone's' guess. Your wort can only "hold" so much alpha acid before it become saturated and the AAs stop isomerizing.

If you're concerned about your beer being too bitter you can always brew up 20% more LME and add it into your fermenter to up the gravity. You don't need an extended boil. Just long enough to sterilize.

 

[Schol-R-LEA]

If your target OG was 1.080, I assume you meant it to be an Imperial IPA, not a regular American IPA. AIPA's normally have starting gravities in the 1.056 to 1.075 range, and top out at 70 IBUs (according to the style guidelines, which you don't have to follow but which make it a lot easier to discuss things).