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01-11-2011, 02:40 AM   #1
shtank
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 all grain Question?

I'm trying to make the move to all grain but there are a few things I dont understand. Does it matter how much grain you use to make a 5gal batch or do you just need a specific gravity. I see most grain bills are about 10# What would happen if I used 15 or 20#. If my mash tun isn't efficient but I got the same specific gravity using more grain would the end result be the same?

Also how do I calculate my efficiency

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01-11-2011, 02:48 AM   #2
Pommy
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You want to be getting the best efficiency you can with your set up otherwise you will be paying more for the same result. I think an efficiency of around 75%-80% is acceptable. You calculate your efficiency as a percentage of potential gravity, actual OG / potential gravity. Im sure someone will have a good link to a spreadsheet that will calculate it for you or the free trial of BeerSmith is a great tool to help with your brewing.

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01-11-2011, 02:57 AM   #3
eljefe
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Quote:
 Originally Posted by shtank I'm trying to make the move to all grain but there are a few things I dont understand. Does it matter how much grain you use to make a 5gal batch or do you just need a specific gravity. I see most grain bills are about 10# What would happen if I used 15 or 20#. If my mash tun isn't efficient but I got the same specific gravity using more grain would the end result be the same? Also how do I calculate my efficiency
Unfortunately, IMO, there is no simple way to answer your questions, so forgive me if this doesn't fully address what you are asking.

The amount of grain used should directly impact your Original Gravity, for example, if I mash 10 lbs of base grains vs 15 lbs, my OG should be lower than the 15 lb OG assuming I have the same efficiency, mash and sparge with the same ration of water, etc.

However, as you already alluded to, if my efficiency is lower than expected then I can raise the amount of grain to meet a specific OG.

Given that there are several variables that impact the efficiency, I would recommend not worrying about the OG with your first All Grain batch. Rather, go through the process paying attention to your steps and taking a specific gravity at the end. You can then see how far off you are (if at all) and then review what you did to see what improvements can be made.

Here are a couple links I have used in the past which help:
http://www.homebrewtalk.com/wiki/index.php/Efficiency
http://www.homebrewtalk.com/f36/maximizing-efficiency-when-batch-sparging-77125/
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01-11-2011, 03:05 AM   #4
dregus
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You had it right at the end of your post. As you increase the grain bill you will increase the specific gravity. You do need to know your systems efficiency. If you google it you can probably find a method for doing this. I use ProMash software to calculate this but it requires that you brew a few batches on your system.

I would suggest that you start with an all grain recipe from online or a magazine and then see if you hit the original gravity that it suggests. That way you will know if you need to adjust the amount of grain you are using.

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01-11-2011, 03:40 AM   #5
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The other side of the coin is that you use double the grain and get double the OG or double the amount of beer. The latter is good, if you have the room and yeast ;-) Have you done a partial mash? If you have, I bet your AG efficiency will be fine. Add a pound or two extra to the grain bill if you are worried. If you are really worried, have some DME handy. You can always add some to make up for a bad lauter. But it isn't really hard. Fly sparging is easy and batch sparging is even easier.

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01-11-2011, 01:09 PM   #6
RM-MN
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There is also a limit to the amount of sugars that the yeast can consume before they quit. If you make a very high gravity wort (high in sugar) so the potential alcohol would be 20% but your yeast can only tolerate 8% alcohol, you would end up with a very sweet 8% beer because the yeast couldn't tolerate any more alcohol so there would be lots of sugar remaining.

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01-11-2011, 02:01 PM   #7
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For every pounds of grain there is a certain maxium amount of sugar you can extract from it. Base-Pale malts have the highest, and darkest grains have the least. To calculate effiency, brew up a batch. When done lauddering (or after chilling post-boil) measure the gravity and volume of beer. Make the SG into "points" by subtracting 1 and multiplying by 1000... e.i. 1.040 becomes 40. Multiply that number by your volume then divide by your grain in pounds. divide that number by 36 ... thats your efficiency. so....

eff= 1000(sg-1)*vol/(grain weight * 36 )

I used 8.3 lbs of grain, and got 5.1 gallons of 1.050 wort:

50 * 5.1 / 8.3 / 36 = 85 %

That's a very basic formula, and brewing software will be more exact, but it should get you started. Pretty soon, as your method settles down, your efficiency will stabilize too. You soon expect a certain amount of point-gallons per lb of grain. It's the above formula, except dont divide by 36. I expect, from my setup, to get about 30 point-gallons per lbs of grain.

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01-11-2011, 03:17 PM   #8
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It's always good to have some DME (extra light, or light) on hand in case you really miss your target, and really want the higher gravity. I didn't have that for my first AG batch, and while the OG was high enough for a style, it wasn't enough to hit my target style. You can also use the DME on hand for making yeast starters (also a good idea)... So it's not like it will not be used at all. For the first few batches have 1-3#'s of DME on hand, just in case.

It will take at least a few batches to figure out your system efficiency. I'm still in that stage myself. In my first AG brew, I really screwed the mash up, so my efficiency was pitiful. With my second, I went back to a more traditional BIAB method. I got just over 81% efficiency there. I'm debating going with a full batch size mash for the next one (no sparge) to see how that goes. I got a couple of holes in my grain bag during yesterday's brewing (caught on the thermometer's shield, and got two small holes in it) so I need to get a couple more grain bags (want to have one 'spare' just in case)...

Couple of other things that will help your brewing... Get a wort chiller, if you don't already have one. Or, if you're so inclined, make one. I made an IC with 20' of 3/8" copper tubing. I have about 19' worth in the wort come time to use it. I'm able to get the wort from boiling to <70F in under 15 minutes using cold tap water.

Keep something else in mind... If you're brewing on the stove top now, you'll probably want to shift to outside as soon as it's not bitter cold out. Get a high enough BTU propane burner, and a couple of tanks (always good to have a full one in reserve) and you'll be happy. I'm planning on doing that come spring time, getting a larger pot so that I can do full boil volume (post mash) mashing (or no sparge)...

I would also suggest getting a good thermometer that can handle the long boil times. I thought I had one to use (a candy/oil thermometer) until yesterday's brewing... It started going weird on me partially through the boil time. It pretty much died, and gave false readings, during my cool-down period. Before my next brewing, I'll need to get a reliable thermometer to use, that I can either just leave in the pot, or have a probe that will be good being inside the wort. I expect to be brewing in another 2-4 weeks, so I'll have to get a new thermometer within that time frame. Keep in mind, I only used the thermometer for six brews.

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01-11-2011, 03:28 PM   #9
ETCS
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I was doing some reading on Wiki this morning. This aritcle finally made it all make since to me:

http://www.homebrewtalk.com/wiki/index.php/Efficiency

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01-11-2011, 03:32 PM   #10
Teaman
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Try tastybrew.com and click on calculators. You'll see a complete recipe calculator. You can mess around with grain amounts and change the efficiency and batch sizes to see how it all works together. I use it for my recipes, but you can just play around with it as a learning tool. All the basic variables are adjustable.
As mentioned above 75-80% is probably the norm when it comes to efficiency.

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