Author Topic: Really Low OGs  (Read 9692 times)

danholmes

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Really Low OGs
« on: May 25, 2005, 01:36:54 PM »
How dies beersmith handle the loss to trub and chiller volume? My efficiency into the boiler has been right-on or even higher than the estimate, but my OG after a 60 minute boil is almost always too low (often by ten points or more). I lose 1.5 gallons to the bottom of my kettle/chiller (it's very wide). I'm thinking that my OGs are so low because Beersmith is not figuring the 1.5 gallons tof trub into the recipe. I'm thinking I should scale my recipies to 6.5 gallons and set my loss to trub at 0. What are your thoughts? I should say that the low OGs have been common to multiple batches since I've strarted using Beersmith.

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Re: Really Low OGs
« Reply #1 on: May 26, 2005, 12:13:57 AM »
Dan,
 The losses (trub, chiller, etc) are only factored into the water calculations and do NOT affect the predicted OG.

 The reason for this is that the standard method for predicting OG is to use only the "theoretical" OG times the overall brewhouse efficiency.  This means that to account for large trub or chiller losses you need to lower your overall brewhouse efficiency.

 This may seem a bit counterintuitive, but if I went with another method such as actually calculating the effects of each system loss then BeerSmith would not be compatible with the other programs and formulas commonly used in brewing.

 I have considered a modification that might "optionally" allow the user to enter their "mash efficiency" instead of brewhouse efficiency and then perform the loss calculations from that point.  This is a possibility for a future release, but I have not yet implemented it.

Cheers!
Brad
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Offline bonjour

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Re: Really Low OGs
« Reply #2 on: May 26, 2005, 02:26:10 AM »
Dan,
set your Batch size to 6.5 gal to account for your trub losses, and leave your losses at 1.5 gallons.  Any volume calculation would need to know the losses.

Fred

danholmes

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Re: Really Low OGs
« Reply #3 on: May 26, 2005, 04:11:28 AM »
Whew! This stuff always confuses me. So by lowering the efficiency, I would increase the grain bill?

Alternatively...Fred-
Why would I leave my losses to trub at 1.5 gallons if I increased the batch size to 6.5?

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Re: Really Low OGs
« Reply #4 on: May 26, 2005, 09:00:37 PM »
Two points,  
1. you need to know what volume you need to boil to get the volume you wish to bottle or keg.  For this reason you need to know your system losses.

2. To get the OG you want you need to know what your "brewhouse" efficiency is.  The only purpose of other efficiencies is bragging rights, and bragging rights do not make better beer.  Your grain bill has a very will defined potential.  The question is, how much of this potential gets into your beer?  This is the brewhouse efficiency,  

Tweak the efficiency of the recipe that gave you a low OG until the predicted OG matches your measured results.  Use this efficiency to calculate your grain bill.  The results will be much closer to what you thought you would get.  This technique will automatically account for the way you brew.

I set my  "Batch Size" to my desired final volume plus known post boil losses.

Fred


danholmes

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Re: Really Low OGs
« Reply #5 on: May 27, 2005, 04:46:27 AM »
Makes sense. Thanks Fred!

danholmes

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Re: Really Low OGs
« Reply #6 on: July 01, 2005, 03:31:11 AM »
Okay Brad and Fred, I'm finally getting a chance to brew again...we just had a baby 5 weeks ago.

I'm trying to calculate my recipie based on our discussion. I lowered the efficiency of my last batch until my OG matched my estimate, I came up with 57%. Then, I scaled my new 10 gallon recipie with a 57% efficiency and a batch size of 11.5 gallons (because I lose 1.5 to trub, etc). I didn't check the box "scale boil volume based on equipment" because it gives me way too much water, not sure why.

The grain bill seems very high for a Pale Ale. Can you look at the recipe? It's here: http://www.danielholmes.net/download/

Do you think making my crush a bit finer would increase my efficiency and lower my grain bill a bit?
« Last Edit: July 01, 2005, 03:39:47 AM by danholmes »

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Re: Really Low OGs
« Reply #7 on: July 01, 2005, 04:31:47 AM »
Daniel,
 Congratulations on the new baby!

 I looked over the recipe and it looks good to me.  I did not see anything unusual.  I personally would use a mash temperature of around 154F, however, since you are probably not shooting for a light bodied ale here (high starting gravity and an APA).

 Yes, your efficiency will increase as you go to a finer grind.  You basically want to mill the grains as fine as you can without creating a stuck mash in your mash tun.  It is a delicate balance, but generally you want to go as far as you can while still retaining some husk integrity in the ground husks so they can serve as a filter bed for the ground grain.  It may take some trial and error to get the right settings.  If you get a stuck mash during the lauter you will know you went too far.

 Happy brewing!

Cheers!
Brad
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Re: Really Low OGs
« Reply #8 on: July 01, 2005, 04:59:48 AM »
Your Lauter Tun Dead Space (equipment setting) is set to 2 gallons.  Do you really have 2 gallons of loss (wort) left in your lautertun (not including the liquid held by the grain)?

That is a lot.

On Crush,  the rule of thumb is to crush until you are scared.  Keep about 4 oz or rice hulls /5gal of beer brewed.
 If your mash sticks, add the rice hulls, mix in and restart your sparge, then back off your crush just a tad for next time.  The rice hulls are great to keep on habd for Stuck Mash emergencies.

Fred

danholmes

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Re: Really Low OGs
« Reply #9 on: July 01, 2005, 09:50:09 AM »
Thanks, guys. I'm going to try making my crush a bit finer.

I batch sparge to I use a big white cooler which is why I have the 2 gallon deadspace. I figured the two gallons by pouring a gallon at a time until water came out the spout (no grain). Is that an incorrect way to measure the dead space?

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Re: Really Low OGs
« Reply #10 on: July 01, 2005, 04:06:44 PM »
That is not dead space.  Dead space would be pockets of liquid in your mastun that you cannot drain.  Most of the space you are talking about is taken up by the grain.

BeerSmith calculates the grain absorption.  Try making this zero and see if that fits your brewing experience better.  (it will be a lot closed to zero in a cooler setup than 2 gallons)

Put a tube to the bottom of of the cooler.  That will drain almost all the water/

Fred
« Last Edit: July 01, 2005, 04:09:46 PM by bonjour »

danholmes

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Re: Really Low OGs
« Reply #11 on: July 02, 2005, 04:19:13 PM »
Brewed the APA today and had much better results. My OG was over by about 10 points but I think that is because I made my crush a lot finer therefor had much better efficiency. I added some water to the boil at the end to lower the OG to the number I wanted. Next time, I will base my recipe on the Brewhouse efficiency I acheived today (69%). Make sense?

I changed my dead space to .25 gallons

Fred, what figure do you use for "Cooling Loss Pct?"


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Re: Really Low OGs
« Reply #12 on: July 02, 2005, 05:23:16 PM »
I use 4% for cooling loss %
This is the volume loss from the cooling of the wort from near boiling to room temp.  Very few brewers will use a different number.  

69% is where you should start.  don't be suprised if this number changes as you gain more experience and refine your technique.

Fred

danholmes

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Re: Really Low OGs
« Reply #13 on: July 05, 2005, 02:32:16 PM »
Brad and Fred-

Sorry to beat this to death guys. Earlier we talked about scaling my batch size to 11.5 gallons if I want 10 gallons of beer in the fermenter (to account for my 1.5 gallons lost to trub/chiller/tubing). Essentially I'm making 11.5 gallons of wort and only using 10 gallons. Fred, you had mentioned also leaving my Losses to Boil Trub and Chiller at 1.5 gallons to get the correct boil volume. When I leave the 1.5 gallons  in, however, my final volume is too high (since my 1.5 gallons is not really "lost" it's just not used). Does that make sense? Remember that I'm shooting for 10 gallons in my fermenter.

Do the math with me, if you don't mind. Here is the screen shot of my boil volume calculations: http://www.danielholmes.net/download/screen.gif

So: 16.29 (volume)-2.81 (boil off)-.48 (cooling loss)=13 gallons left in my kettle after the boil. So now I pump over to the fermenter (leaving 1.5 gallons to trub, etc) and I end with 11.5 gallons in the fermenter (13-1.5=11.5). But, I want 10 gallons in the fermenter, so wouldn't it make sense to set the Losses to Boil Trub and Chiller to 0, which would give me 10 gallons in the fermenter?

Dan



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Re: Really Low OGs
« Reply #14 on: July 06, 2005, 03:26:45 PM »
Quote

So: 16.29 (volume)-2.81 (boil off)-.48 (cooling loss)=13 gallons left in my kettle after the boil. So now I pump over to the fermenter (leaving 1.5 gallons to trub, etc) and I end with 11.5 gallons in the fermenter (13-1.5=11.5). But, I want 10 gallons in the fermenter, so wouldn't it make sense to set the Losses to Boil Trub and Chiller to 0, which would give me 10 gallons in the fermenter?

To hit 10 gallons in the fermenter with these numbers you wat to start with 14.4 gal in the kettle (at temp) vs. your 16.29.

Set your batch size to 11.5 gal to account for the 1.5 gal loss to trub (which contains sugars) to get the OG you are targeting.

Note that the amount of trub will vary depending on your hopping schedule (Whole/pellet), and if you chill with an imersion or counterflow chiller.  This figure is based on experience and isn't calculated

Fred

« Last Edit: July 06, 2005, 03:29:47 PM by bonjour »