Mash/Sparge Concern for Imp. Stout

[hanuswalrus]

So I'm brewing my first Imperial Stout this weekend. Doing a 3.5 gallon batch with a total of 15.85 lbs of grain. What concerns me is that when I enter my numbers into the mash/sparge water calculator (I use this one: http://www.brew365.com/mash_sparge_water_calculator.php ) it gives me a mash water volume of ~6 gallons (1.5 qts/lb) and a sparge of ~1 gallon. Does that sound accurate to everyone? I've never done a beer this big, and typically my mash and sparge water are split almost evenly so it raises a little concern.

Also, it seems like it would be impossible to hit a proper mash out temp only adding 1 gallon of water to almost 16 lbs of grain, even if the water is boiling. I was thinking it might be important to mash out with so many roasted malts in this beer. Should I just hold off on adding all the roasted malts until about 15 mins left in the mash?

Any tips, tricks or advice would be greatly appreciated as this will be one of the more expensive beers I've brewed, not to mention the months of aging I'm planning for this beast

 

[blizz81]

In a big beer like this where your first runnings will account for a lot of your normal preboil volume, you more or less have two options:

- take the efficiency hit that will come with not using much sparge water
- up your preboil volume (allowing for somewhere around equal volumes of first runnings and sparge) and extend your boil time to boil down to your desired batch size while maintaining similar efficiency


Going along with option 1, you could add some DME / LME into the boil to help get closer to your OG.


Late addition of roasted malt in the mash shouldn't be a bad idea, there's some recent threads you can read up on in that respect I think. I wouldn't be too concerned with a mash out, though I'm never concerned with a mash out (I get first runnings on heat immediately is about all the further I worry).

 

[hanuswalrus]

Thanks blizz

OK, I think I'll add a couple extra lbs of base grain to the recipe as I don't have the kettle capacity or strong enough heat source to increase my preboil volume.

Anyone else have any additional advice?

 

[blizz81]

Thanks blizz

OK, I think I'll add a couple extra lbs of base grain to the recipe as I don't have the kettle capacity or strong enough heat source to increase my preboil volume.

Anyone else have any additional advice?

One thing I do for really big beers if I decide to go the "I want to brew this at my normal efficiency" route is I'll keep some runnings on heat, and add to the BK once it boils off a certain amount.


ie, I'm able to obtain a 10gal preboil volume in a 10gal pot by starting with 8gal, boiling for 90 minutes down to 6gal, then add the remaining 2gal to get back to 8gal (and boil for another 90 minutes to get back down to 6gal).


I think more brewers go the "take the hit on efficiency" and / or add some extract / sugar / etc route.

 

[hanuswalrus]

So now I've just decided to attempt a parti gyle with this. It seems like wayy too much potential wort to just throw away. I now have a total of 19.15 lbs for the total grain bill.

Now my question is, after I mash and collect my full volume for the first runnings batch of imperial stout, is it recommended to just add the amount of water to the mash that you would like to get as a total preboil volume for the second batch? Have the mashed grains reached the maximum saturation at this point?

Also, is it recommended to just add distilled/RO water for the second batch? Does the pH of the first runnings batch carry into the second runnings for the second batch? I'm assuming it does just like with a normal batch that has a sparge involved. Probably a stupid question..

 

[madscientist451]

Your recipe calls for 15.85 lbs of grain and you are going to use 19.15 lbs, seems likely that you'll overshoot your pre-boil gravity and then of course your post boil will be higher as well. One technique I've heard of is to use 2/3 first runnings and 1/3 second runnings. But I think you have to experiment a little to get your pre boil gravity right. If I was going to try it, I'd run off the first runnings but not boil yet, then run off the second runnings, but not the same volume as the first time, maybe only 2/3 the first amount. Then pull some samples and see what you get. Try 2/3 cup of first runnings and 1/3 cup second and see what your gravity is. If its in the ballpark, make the appropriate blend and get boiling. You might have to go 3/4 first and 1/4 second, You'll have to see what you get. Mix up the leftovers and boil that. After you do it a few times you can tweak it down to where you want it for your system and skill level. Some breweries will make a first runnings beer and a second runnings beer and then blend them after fermentation to get the desired result.