Falling short of target gravity - preboil

[lateforwork2]

Hi all, I'm new to all grain but I've been trying to absorb as much information as possible. Being new I'd like to err on the side of caution and assume that I will not hit the efficiency I'm looking for the first time. Given that I think I need some general understanding help......

So for example I'm going to brew a Saison-- (this is all theoretical)

Original Gravity target: 1.060
Batch Size: 6 gallons
Pre Boil Size: 8 gallons
Pre Boil temp Sample: 150 F

Pre boil calculation requirements –
6 gallons * 60 Gravity Units = 360 GU
360 GU / 8 Gallons = 45 GU or 1.045
1.045 temp adjusted (for 150F) = (1.045 - 0.018) = 1.027 (this is what I need to see on the hydrometer to have met my OG)

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So Assuming All of this is correct let’s say that I miss my 1.027 and come in Low at 1.022 (still pre boil) –
I take 1.022 and add 0.018 to come out to 1.040 or 40 GU
40 GU * 8 gallons = 320 GU or 40 GU shy of what I wanted to achieve for my final 6 gallons.
320 GU / 6 gallons = 1.053 (6 GU per gallon short)

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Assuming all of the above is correct – I need to use something to bump the numbers, I’ve heard LME is good to have around for first time all grain brewers.
If this is correct:

LME contains
[(1 pound) * (36ppg)] / (6 gallons) = 6 points, or 1.006 -

So adding one pound to my brew would bump it the necessary 6 GU per gallon that it was short?

EDIT: It looks as though this is correct.

 

[mtnagel]

Maybe it's just me, but I don't worry if I'm off by a few points. I'm not selling the stuff. I made an imperial stout that was supposed to be 1.106, but I only got 1.092. I didn't correct anything. The FG dropped lower than I expected, so the %ABV was similar to what I was expecting so no big deal in the end.

 

[lateforwork2]

Maybe it's just me, but I don't worry if I'm off by a few points. I'm not selling the stuff. I made an imperial stout that was supposed to be 1.106, but I only got 1.092. I didn't correct anything. The FG dropped lower than I expected, so the %ABV was similar to what I was expecting so no big deal in the end.

I probably wouldn't either in all actuality....this was just more of a "what if" in the case that I come up very short. I like knowing how the numbers influence the others.

I just hope my math is correct Hopefully someone can verify!

 

[CRoth36]

Right now I wouldn't worry about hitting it dead on. This is something you might want to concern yourself with later on when trying to repeat brews. Personally I never calculate efficiency. I just know what does what on my system. For example, if I want to do a high alcohol imperial stout I know for the most part how much grain I need to use. Why I'm saying is dont spend time worry about efficiency. Just brew and it'll start comin naturally to you.

 

[tootal]

I agree with those above. Take a recipe and make it. Check your OG. Is it high or low? Adjust your recipe to raise or lower your OG. Everybodies system is different and you just have to learn your system. If you use any brewing software it needs to know your efficiency so brew a solid recipe, learn your systems efficiency and plug that into your software. The software should have a program to tell you how efficient you were. Once it knows your system it can calculate the amount of malt you need more accurately. If you're not using any software then I highly recommend trying it. There are free versions out there that will make it easy for you.

 

[BackAlley]

Don't use your hydrometer at 150. Cool the wort to at least 90. Adjustments that large are notoriously inaccurate. Better eat get a refractometer.

 

[lateforwork2]

I agree with what you guys have to say...its more about having fun brewing...And I probably wont actually use this in the real world, but can anyone verify my math / thought process?

 

[Jorb]

I agree with what you guys have to say...its more about having fun brewing...And I probably wont actually use this in the real world, but can anyone verify my math / thought process?

It looks right to me. I had to add some DME to a batch a few weeks ago.

 

[Kingbogart]

There was a good article posted on calculating your brewhouse efficiency just recently, you can find it here
https://www.homebrewtalk.com/entries/take-the-guessing-out-of-efficiency.html.

From what I understand of it, your logic is correct. As you can see above, many people don't actually concern themselves with hitting their numbers spot on. After using your system for a while, you will become aware of your own efficiency, so adjusting may be less necessary.

If you are interested in adjusting, and have come out low pre-boil there are a couple of different options. Adding LME or DME will both increase your pre-boil gravity and put you more in line with what you were shooting for. Be sure to check the manufacturer and type of additive being used, as the gravity in each can vary. This will get you closer to your recipe's OG, and the same volume. You can also adjust your hop schedule to account for a longer boil, and end up with the correct gravity, but less volume. Either way should work, one costs more money, the cost of DME or LME, the other costs more time since it's a longer boil.

If you were to overshoot on pre-boil gravity, you have similar options. You can either make a stronger beer at the same volume, or dilute by adding water to the correct gravity and have more beer.

 

[lateforwork2]

I appreciate all the replies. I will probably measure my first batch just so I can calculate everything out and see where I stand. Do you guys suggest LME or DME?

 

[Jorb]

DME is easier to weigh and deal with it. LME is fine in kits but I would hate to try getting half a pound out of a bag or can.

 

[smyrnaquince]

I haven't used either, but I believe that it is easier to store partially-used DME than LME.