Tips on brewing imperial beers

[rubiconbrewer]

Hi,

I've made 2 imperial all grain beers and each time I've been short of my target og. The first imperial ipa was 20 points short. Today I made a russian imperial stout and came 10 points short.

I use a 10 gallon round water cooler with stainless steel mesh connected to compression fittings for my mash tun

Any tips on improving efficiency and hitting target og would be much appreciated! Thanks!

 

[VikingChrisColby]

How much wort are you collecting per pound of grain? Are you collecting the same amount as you would for a moderate-gravity beer? If so (and you're far from alone in doing this), you're leaving wort sugars behind in your mash tun. If that's the case, collecting more wort and boiling it longer will help.

This might help as well:

http://beerandwinejournal.com/big-wort-production/


Chris Colby
Editor
beerandwinejournal.com

 

[runkelia]

There is a lot to consider, was your grain crushed sufficiently? Did you stir enough, sparge method? If you are consistent in your process, the easy answer could possibly be to add more grain, meaning account for a lower efficiency on your next brew.

 

[wingedcoyote]

You may already be doing this, and it isn't a real solution, but my first step would be to keep a lot of DME on hand and use it to boost up any low-performing mashes. Results may not be the same as if you had hit target OG, but IMO it's better than having an IIPA come out as a superbitter APA.

 

[rubiconbrewer]

How much wort are you collecting per pound of grain? Are you collecting the same amount as you would for a moderate-gravity beer? If so (and you're far from alone in doing this), you're leaving wort sugars behind in your mash tun. If that's the case, collecting more wort and boiling it longer will help.

This might help as well:

http://beerandwinejournal.com/big-wort-production/


Chris Colby
Editor
beerandwinejournal.com

there were 17.25 pounds of grain and I did 4.3 gallons mash in and sparged 5.5 gallons. So my pre boil was a little over 7 gallons.

How much water should i be using at mash in and sparging?

Thanks for your reply

 

[runkelia]

My batch sparge process with 1.25 ratio, says you should start with 21.6 quarts or about 5.5 gallons. Rest for 1 hour. Collect, and measure what you collect, I use a notched dowel. My guess you collect between 2.5 and 3 gallons. If you are aiming to collect 7 gallons like I do, your sparge water volume = 7 gallons - Vol. 1st runnings / 2. So you may be sparging with 2 gallons twice. That is how I do it, but your way you still collected 7 gallons so you're not wrong.
You probably need a couple more brews to dial in your efficiency.
If you know your process gets you 10 points under everytime, then you add into your plan how to account for those 10 points. Like adding DME, or collecting say 8 gallons and boiling an extra hour. Hope this helps.

 

[rubiconbrewer]

My batch sparge process with 1.25 ratio, says you should start with 21.6 quarts or about 5.5 gallons. Rest for 1 hour. Collect, and measure what you collect, I use a notched dowel. My guess you collect between 2.5 and 3 gallons. If you are aiming to collect 7 gallons like I do, your sparge water volume = 7 gallons - Vol. 1st runnings / 2. So you may be sparging with 2 gallons twice. That is how I do it, but your way you still collected 7 gallons so you're not wrong.
You probably need a couple more brews to dial in your efficiency.
If you know your process gets you 10 points under everytime, then you add into your plan how to account for those 10 points. Like adding DME, or collecting say 8 gallons and boiling an extra hour. Hope this helps.

Thanks for your help! I"m thinking next time Ill just collect more and have to do a longer boil. I like your idea on the dme, next time I'll be sure to add some to bring gravity up. Sparging twice sounds like a good idea too, I'll try that too

 

[VikingChrisColby]

there were 17.25 pounds of grain and I did 4.3 gallons mash in and sparged 5.5 gallons. So my pre boil was a little over 7 gallons.

How much water should i be using at mash in and sparging?

Thanks for your reply

There's your problem. You had 17 pounds of grain and you only collected 7 gallons of wort. With 17 pounds of grain, you could collect at least 8.5 gallons of wort — with 10 gallons being a more reasonable volume. You left a ton of sugars behind in the grain bed.
Of course, collecting more wort means boiling longer to reduce it to your target volume. But from an extract efficiency standpoint, you've got to rinse all the sugars out of the grain bed completely to get the best efficiency.


Chris Colby
Editor
beerandwinejournal.com

 

[Calichusetts]

I actually get higher efficiency with my big beers. I try to have a balanced grist-water ratio for the mash but do 2 or even 3 sparges. And I always do an extended boil, 2-3 hours. In the end, same final volume, OG is usually spot on, sometimes even a little higher. You just need to make sure you have large enough equipment to handle more volume

 

[runkelia]

There's your problem. You had 17 pounds of grain and you only collected 7 gallons of wort. With 17 pounds of grain, you could collect at least 8.5 gallons of wort — with 10 gallons being a more reasonable volume. You left a ton of sugars behind in the grain bed.
Of course, collecting more wort means boiling longer to reduce it to your target volume. But from an extract efficiency standpoint, you've got to rinse all the sugars out of the grain bed completely to get the best efficiency.


Chris Colby
Editor
beerandwinejournal.com

I have been looking for this answer for some time, I guess I didn't know how to ask the question until now, as I have done (2) batches @ 15 lbs and came out 1.070 which I thought could be improved on.
What is the standard for how much you should collect based on your grain bill?
Your reply of 8.5 gallons for 17 pounds tells me 1/2 gallon per pound.
Is there a more exact answer?
Thanks for your reply.

EDIT: Cancel request. I have read your article on batch sparging from October 2013, and I really wished I read that months ago. The answer is .58 gallons per pound with 2 sparges.
Cheers

 

[VikingChrisColby]

The answer is .58 gallons per pound with 2 sparges.
Cheers

The exact number depends on a few things, especially the pH of the final runnings of your wort. Around 0.5 gallons of wort per pound of grain is what I'd consider the minimum amount of wort to collect and get a reasonable extract efficiency. My average is around 0.65 gallons per pound when I sparge until the the gravity and pH (and flavor) of the runnings indicate that I should stop.


Chris Colby
Editor
beerandwinejournal.com

 

[rubiconbrewer]

Well I've done another batch. This time I improved a little bit. 17 pounds of grain. hit 1.074 og. I mashed in at 156 this time instead of 151.

This time I collected approx 8.25 gallons and I crushed my own grain with my barley crusher. I also stirred twice as much as the last time I made an imperial beer. 75% efficiency would be 1.085. so i'm 11 points off.

How much should I be stirring? I've been stirring every 15 min when I check the temps and once in between each temperature check.

I mashed in with 6 gallons and sparged 3 different times (2gal, 3 gal, 3 gal)

The only thing I can think of is that I need to start with 12 gallons pre boil? Any recommendations?

 

[eric19312]

Chris' write up on brewing big beers is excellent resource.

Easy answer is just don't plan on 75% efficiency in big beers. You have done 3 big beer batches now, take your average efficiency from those and use that as your expected efficiency for your next beer. Scale the recipe accordingly.

Eg if your average was 65% efficiency on big beers and your recipe assumes 75% efficiency, you will could try increasing your grain bill by about 15%. (about 19.5 pounds of grain instead of 17...) In theory, over time you will refine your expected efficiency at different gravities and get good at hitting your OG. Probably you will improve techniques too and get better efficiency from that so your expected efficiency may drift up over time to a point.

I am personally still not there yet on bigger beers. What I have to do is take a gravity measurement pre boil. A refractometer really helps here cause getting a good reading of hot wort is a problem with a hydrometer, adjustment table or no. I then use an evaporation calculator (in Beer Alchemy, there are online versions check brewer's friend) to determine what my OG will be at planned final kettle volume. If gravity is projected too low I have a few choices. (1) Accept less beer reaching fermenter at the correct gravity. (2) Accept lower gravity with planned volume. (3) Correct with DME.

Or (4) do what I did last brew and sparge some more. I realized I was going to be 10 points low, so I added some more sparge water and collected another 1.5 gallons. Added that to the kettle, mixed, rechecked pre boil gravity and volume, calculated OG at 11 gallons post boil, and was spot on. Ended up needing a 2 hour vigorous boil instead of the 90 min sedate boil I planned. Ended up hitting 1.074 from a target 1.073.

 

[rubiconbrewer]

Thanks for the reply! Yeah I agree Chris' article is very helpful.

I think I'll try increasing the grain bill next time and if that isn't enough I'll def add some malt extract to it. Despite not hitting og I've been making some great beers and been having fun too. I've at least been seeing improvement every time.

Do you think the the .039 gap on my mill is a good setting?

Thanks for the tip on the evaporation calculator that should help me quite a bit and I'll know whether or not I need to add dry malt extract or not!

Thanks again for your advice! Trying to learn all I can to perfect this!

 

[pigroaster]

I would set mill at.030 or a credit card in thickness and mist (condition) grain 20 minutes before rolling with mill, 2 oz of water in grain and mix well. The husks will not crumble so much and efficiency will go up.

 

[rubiconbrewer]

I would set mill at.030 or a credit card in thickness and mist (condition) grain 20 minutes before rolling with mill, 2 oz of water in grain and mix well. The husks will not crumble so much and efficiency will go up.

Alright thanks I'll give that a try!

 

[eric19312]

Improving your crush through grain conditioning might help your efficiency but
I doubt it will be the improvement you are looking for. The factory setting on the barley crusher is really a pretty good place to start.

Note I mainly say this because you complained about lower efficiency with bigger beers. If you are also getting low efficiency with beers in the 1.040 to 1.060 range then crush would be a good place to focus.