Author Topic: High Gravity Brewing  (Read 9666 times)

Offline MmmmBeer

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High Gravity Brewing
« on: May 03, 2010, 06:52:16 PM »
Ok my question is regarding BeerSmith's brewsheet and high gravity brewing.
Regarding the "add water to achieve boil volume of x", I assume this should actually read "do whatever you need to do including boil off until you reach a pre-boil gravity of x and a volume of y".

Does anyone else brew very high gravity beers? 10.5% +?
Assuming an efficiency of 70% where does the line get drawn in the sand between having to boil down and adding water to the boil to obtain the pre-boil gravity?
There is most certainly a point at which first runnings out of the mash will not reach the pre-boil gravity required.
Yes i realize efficiency goes down with higher gravity beers.
I just think that beersmith reads incorrectly when it reports in the brewsheet.
I would love to hear any comments on high gravity brewing with beersmith in addition to the one i posed here.

Thanks All ... Cheers!

Offline Pirate Point Brewer

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Re: High Gravity Brewing
« Reply #1 on: May 10, 2010, 05:18:44 AM »
MmmmBeer,

We are not particularly high gravity brewer's but we're not sure your problem is cased by the gravity alone.

It seems to us that your basic problem is in getting your equipment settings nailed down. This take a bit of work but its not bad.

For a moment think of volume and gravity as separate issues. If you are set up to make a full wort boil, then you should only need to add water if something is not set up correctly. You must carfully account for all of your volume losses in the equipment set up. Easily done by carefully measuring volumes at each step. You need to get them set up so that you never need to add water.

The first and most common loss is in you MLT due to the false bottom/manifold/braid system that you use. You can set this by carefully measuring your run off using just water and no grains. The difference between water in and water out is your loss. Tipping is OK. Just remember that if you set it up tipping, you must always tip.

The second is also in the MLT but it is due to absorption by the grains. As above, this can be accounted for by careful measurement of your first running.  If the loss above is set, then the difference between total mash volume and your first running volume is your absorption loss. It is set by dividing the loss by the number of pounds of grain in the MLT. The default is very close for most grain bills.

The third is your Evaporation loss. This is determined by the shape of you boil pot and the vigor of your boil. it can also change a little due to ambient conditions of local temp and humidity. This can be measured by just carefully boiling a carefully measured volume of water for one hour. The difference of water in minus water out is this evaporation loss. The water out measurement should be made before chilling so be careful. Any small variation due to ambient can be accounted for below.

The fourth is your Loss to Trub and Chiller. You can get a start at setting this by measuring the run offs using just water. If you chill with an IC, then you won't have a chiller loss. If you use a CF (counter flow) there can be a fair amount of wort left in the coil. Like tipping, you can try to get it out. If you set up by doing this, you must always do this. Plate chillers have a very small loss that is more difficult to recover. We use a plate and don't try as the loss is small. This only accounts for the chiller part of this loss. The trub loss must be done by trail and error. Some wort is almost always left in the boiler to prevent pulling too much junk from the bottom of the boil pot into the ferment er. This is where we make all of our fine and final adjustments. Start out with .25 or .5 gallons. As you make a batch and all other losses are set, you adjust this to a value that allows you to collect your required batch volume with clean wort.

The 4% shrinkage due chilling is usually close enough.

The last place where volume errors occur is in the sparge. If you Batch sparge. Then its just volume in should be voulme out as the grains are saturated. Remember, if you tip to make your volume, then you must tip with each running of your sparge. We usually set up to batch sparge using 100% of our tun volume, with equal sized batches. We always drain the tun before sparging. Fly sparging to a gravity target is more difficult as depending on you mash efficency, volume is the variable. So we don't. Fly sparging to a volume is not as complicated as your variable is gravity not volume. Many of the Grand Master Brewers Fly sparge very successfully. If you choose to fly sparge to a gravity, they will help you out.

Once you have your volumes under good control, you can attack your gravity with recipe adjustments while you work to improve your mash efficiency. Don't chase gravity/efficiency until you have volume under control or it will drive you NUTS!!

To prevent having an unsatisfactory batch while working on you efficiency, you have the two basic alternatives if you must hit a gravity target. If your pre boil gravity is low, you can boil longer and accept a smaller batch. This requires measurement during the boil to re-plan your hop additions. Or you can add extract to correct the gravity up to target. If your gravity will be high - bottle it and send it to us! Seriously, if your gravity is going to be high, you can add water to dilute it and make a larger batch than planned, or separate some to boil for yeast starters.

Wow, we said allot. Sorry for being so wordy. We hope this helps

Preston
In Fall and Winter, we burn wood in the fireplace and brew beer.
In Spring & Summer, we're on the water or walking the beach!
 Then back at the dock we create a reason to brew!

Offline MmmmBeer

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Re: High Gravity Brewing
« Reply #2 on: May 11, 2010, 04:21:48 PM »
Thanks for the response Pirate Point.
We have been using beersmith for about 5 years now and the system and it's volumes are set properly, for a 6% beer. Evaporation rate is still a little tricky since it varies by how aggressive the boils is.

My problem is that when brewing a 6% beer, we hit pre-boil targets (both volume and gravity) perfectly as well as hitting o.g. and volume numbers into the fermenter. When brewing 10.73% (estimated) Russian Imperial Stouts we fall way short on gravity and high on volume. We are not maxing out our mash tun by any means. Brewing a 8 gallon batch using 25 gallon pots.
For an example our last Russian Imperial went into the boild pot at 1087 (supposed to be 1100) with a pre-boil volume of +/- 11.5 gallons (supposed to be 9.82 gallons). We are using a fly sparge process and this particular recipe only called for 2.22 gallons of sparge water. Assuming a lower efficiency rate for high gravity beers i used 62% to create the recipe. Our 6% IPA recipe uses a 70% brewhouse efficiency and hits perfect every time.

If you can solve this riddle, i would be more than happy to send you a bottle of our "Arrogant Bastard" clone that was aged to perfection for 3 months in a Jim Beam Bourbon barrel. Mmmmmm Beer!!!!

Offline MaltLicker

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Re: High Gravity Brewing
« Reply #3 on: May 12, 2010, 01:28:38 PM »
If your settings for a 6% beer are perfect, and you're now making a (almost) 11% beer, is a 8% drop in EE% enough of a hit? 

A 6% beer might have 12# grains?  The 11% beer might take 22#, at the same EE%, so at lower EE% it would take what?  26, 28#?  That is a big difference in grain weight, fluid dynamics, lauter tun design, etc.

Post your equipment profile and recipe and we'll see if anything leaps out. 

Offline Pirate Point Brewer

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Re: High Gravity Brewing
« Reply #4 on: May 12, 2010, 03:45:04 PM »
MmmmBeer,

I understand where Maltlicker is going, but I still wonder if the basic problem is with volume.  Its very difficult to base decisions on efficiency if volumes are not consistant. As I understand your last post, you wanted a volume of 9.82 gallons @ SG of 1.100. Just plugging your result, 11.5 gallons @ SG 1.087 into the BeerSmith Boil Off Tool, we find that if you boil the 11.5 gallons for 75 min @ 12% evap, you'd end up with 9.38 gallons @ SG 1.107.  We could play with Evap & Time and probably get your numbers exactly.

My point and I think Maltlicker's is that the sugar is there in the right proportion, the pre boil volume is incorrect. If you have too much water from the mash, and too little for the fly sparge, but the gravity is there once the volume is correct .... let's also review the Mash Profile.  You can easily get too much water here in the mash and have very little left for sparging.

Preston
In Fall and Winter, we burn wood in the fireplace and brew beer.
In Spring & Summer, we're on the water or walking the beach!
 Then back at the dock we create a reason to brew!

Offline MaltLicker

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Re: High Gravity Brewing
« Reply #5 on: May 13, 2010, 10:12:36 AM »
You can easily get too much water here in the mash and have very little left for sparging.  Preston

Preston's right.  I meant to say that 2.2 gallons for sparging seemed low.  Which is why I asked for your files to review.  Esp. on a really big grain bed, 2.2 gals would not cut it.

Offline SOGOAK

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Re: High Gravity Brewing
« Reply #6 on: May 14, 2010, 12:01:14 PM »
I had good luck when I did a slightly modified version of Fred Bonjour's "Da Tubbel wit Dubbel" preboil was 1.080 and post was 1.090 I had monster attenuation to 1.006 (adjusted for brix scale fudge). I don't believe I did anything special other than stir my full mt carefully.  Message Fred, he is very knowledgable on BIG brew.
Good Recipe, Good Ingredients, Good Procedure, Good Sanitation = Good Brew.

Offline MaltLicker

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Re: High Gravity Brewing
« Reply #7 on: May 14, 2010, 12:34:38 PM »
.......
1.090 I had monster attenuation to 1.006 (adjusted for brix scale fudge).

1.090 down to 1.006?  93% attenuation?  That's amazing.

Offline MmmmBeer

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Re: High Gravity Brewing
« Reply #8 on: September 21, 2010, 06:06:52 PM »
Well, thanks to everyone's help on this. Here's the deal...
Just prior to brewing that 10+% RIS, we changed out our bazooka screen for a standard perforated mash screen. This particallur screen was on legs basically 2" tall to hold it off the bottom of the pot. We are using 25 gallon pots. So what did this mean for us and our efficiency? The mash was too dry. 2.5 gallons of the total strike water was sitting below the screen. Since this occured after brewing the 6% and the 10+ was the first beer brewed after the switch, i associated this to a poor efficiency. What pointed me in this direction was a poor efficiency on another beer we brewed that was about 7.5%. To correct this problem in beer smith i entered a negative 2.5 gallons to the Lautter Tun Deadspace. The result is 2.5 gallons more strike water for the mash which has brought us back to realistic 75% efficiency levels for 6-7.5% beers. We have not brewed the RIS again yet but I expect around 65-68% efficiency will be the result.

Thanks again for everyone's help on this. I would not have even considered volumes changing due to the height of the mash screen without you help!

 

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