Brews Brothers Porter Clone

I'm brewing this up today.  I was on a business trip to Reno, Nevada back in October of this past year and had lunch at Brews Brothers Microbrewery at the Silver Legacy Casino.  I had a really nice sweet porter with my lunch.  I spent about an hour talking to the head brewer that day.  I asked how he got his porter to be so sweet and smooth.  He was kind enough to share the recipe.  I'm really looking forward to seeing how close I come.  The recipe he gave me was for a 311 gallon batch.  I used BeerSmith to scale it down to a 5.5 gallon batch.
I did decide to go with a 90 minute mash to make sure I got full conversion.  I also did a decoction mash out.  I pull 1/3 of the thickest part of the mash out and slowly brought it to a boil and simmer for 10 minutes before returning it to the mash tun.  I talked about this with the head brewer.  He said he doesn't do that, because of the time and cost of doing it.  But on a homebrew level, it's something he'd probably do.

The recipe is designed to leave a lot of unfermentables to keep it sweeter with a smooth chewy mouthfeel.  The addition of Pendleton Whiskey with the Vanilla Beans in the secondary adds to the sweetness and ABV.  Pendleton whiskey has a sweeter flavor than most whiskeys.  I basically split and chopped up the vanilla beans two weeks ago and put those in my Ninja Blender with 2 pints of whiskey and emulsified it.  The whiskey/vanilla bean blend is in pints jars awaiting the secondary.

I let you know how it turns out!

I finished my brew day and now I'm looking for input.  I missed my gravities.  A lot!

My estimeated pre-boil gravity was 1.058.  I hit 1.052.  My mash efficiency was 73.6, so not great, but not bad.  I estimate my mash efficiency at 75% anyhow, so missing a little low on efficiency and gravity while not ideal, doesn't bother me a lot.

However, my post boil gravity was 1.063.  My estimated starting gravity was 1.078, so I missed my 12 points.  That's quite a bit.  I probably should have added some DME, but it's been a long day and it didn't occur to me until I starting putting this post together.

I know the possible culprits are:
  Grain crush
  Mash temperature off, but I used two thermometers and my mash in temp was dead on.
  I did lose temperature rather fast.  I used my second mash tun, to try and dial it in better and it didn't hold temperature very well. 
      During my 90 minute mash, it dropped down from 158F to 152F.  I doubt that would have hurt my mash efficiency though.
 
Because I missed my preboil gravity by .006, I was expecting to miss my post boil gravity by the same .006 or close to that.  I didn't expect to miss it by .015!

Any advice or pointers would be helpful.  Even just an explanation of what you think might be going on would be helpful.

Thanks in advance.

Hi Scott;

If you apply the formula:

((Wg x P) / V) x Ef

Wg: Weight of Grain and Fermentables
P: Potential yield of Grain
V: Kettle Volume, Pre or Post Boil
Ef: Mash Efficiency as a decimal number

A different picture of your actual measurements emerge.

Based on the grain weight, 75% efficiency and volumes, I come up with:
At Preboil Volume of 7.44: 1.054
At Postboil Volume of 6.24: 1.065

Both of these are approximates, but closer to your measurements than BS predicted.

This makes me think that something in the equipment profile is causing the discrepancy. Perhaps the Batch Volume is not the same percentage as your Brewhouse Efficiency?

It's also possible that the calculated yield potential for the base malt was higher than what you actually used. Is there a chance that the grain sat crushed, in moderate to high humidity for more than 3 days? If so, this can reduce yield.

Scott-

Did you record your ACTUAL volume measurements?  That would help sort out what brewfun is after...

Second, did you record measurements (vol, SG, temp) from your first and second runnings?  These would help, too. 

74% mash eff. is fine for a double batch sparge.  That's almost exactly what I see for beers in the 1.060-70 range.  However, your recipe was formulated based on an 81% eff. (according to your posted brewsheet).  I formulate my recipes based on an assumed 70% mash eff.  This leaves me plenty of play room to assure that I don't undershoot (as happened here). 

Have you read this?

http://braukaiser.com/wiki/index.php?title=Understanding_Efficiency

This table:

http://braukaiser.com/wiki/images/3/3c/First_wort_gravity.gif

will tell you how your conversion efficiency looks, based on a gravity measurement from the mash.  You can even take this measurement while the wort is still in the grain.  If it is still below 90%, you can leave it longer to get more conversion.  Also, if this measurement indicates 90+ % conversion, but you are still undershooting then you know that it is a lautering issue, and you can focus your efforts in figuring that out. 

My volume measurements were dead on.  I had 7.44 going into the boil pot.  I had 5.5 going into the fermentor. 

The 81% estimated mash efficiency is a BeerSmith number.  I know my total efficiency is jusually at about 75%, so that is what I put in for "total efficiency".  If there is a way for me to put in an estimated mash efficiency, I don't know how to do that.

By the way, my starting gravity was actually 1.065, not 1.063.  It was late, I was tired and I couldn't read my own writing.  Better, but not great.

I'm attaching the Design Tab, the Mash Tab and the Volumes Tab.  I'm also attaching my equipment profile.  I tend to boil quite vigorously, so I do end up with a high boil off rate.

I've also attached an updated version of the recipe, with proper numbers in it.  When I first posted the recipe, I was just beginning the mash.

Gentlemen...I very much appreciate your help with this!

+1 to both of you!!

Based on the data you've presented your TOTAL efficiency was NOT 75%, but was more like 68%.  Here's the rough math (assuming 36 points per lbs per gallon...not really true, but close enough for gov't work). 

14.5 lbs of grain @ 36 pppg = 522 total points.

5.5 gallons into fermenter at 1.065 SG = 358 points into the fermenter.

358 / 522 = 68.5% of the total points available from the grain ended up in your fermenter. 

Your HOT preboil volume was 7.44.  Accounting for cooling shrinkage, that's 7.23gal.  Based on that and your gravity (7.23 @ 1.052 = 376 points), your mash efficiency was around: 376/522 = 72%. 

The "mash eff" from Beersmith takes into account your "tun deadspace" of 0.75 gallons (hot, 0.73 cooled).  It ADDS the sugar left in the deadspace to the sugar in the kettle, and calls that the total sugar extracted from the mash.  Eg:

0.73 * 52 = 38 pts.  (in reality this would be your second runnings gravity, but I don't have that number)

376+38 = 414 points (extracted from grain).  414 / 522 = 79%.

Do you really have a tun deadspace of 0.75 gallons?  That's pretty large.  I would question that number.  The only good way to measure "tun deadspace" is to drain the remaining wort from the MLT after you finish sparging.  I've done it that way, and I'm more like 3 CUPS.  I have a stainless domed false bottom. 

I'm not saying you DON'T, but I've seen many people measure this by filling the MLT with 1-2 gallons of water, and then draining it back out.  Whatever doesn't come out, they call "deadspace".  This is not correct, because it doesn't account for the volume of the tun that is filled by grain.  What many people don't consider is that much of the "deadspace" is actually accessible to grain.  So, the grain displaces MUCH of the wort in the "deadspace" in the mash. 

Ultimately, I think your "issue" was over-estimating your efficiency, which caused Beersmith to overestimate your starting gravities.  Then you adjust the grain quantities down to compensate (or left them alone thinking everything was fine), and therefore didn't have enough grain for reality. 

Your extract efficiency was a little lower than I would expect for a 90 minute mash (at only 77%).  At 90 minutes that should have been closer to 90%.  But, your thickness was 1.44 qt/lbs....a little thick for me.  I generally see lower extract efficiencies for mash thicknesses below 1.5 qt/lb.  I have MUCH better conversion between 1.75 and 2.25 qt/lbs, and it is WAAAAY more consistent.  That can be a pH thing, or a grain crush, or dough-balls, etc. 

Thanks Tom!  I think my first step is to make two changes.  You were "dead on" about the way that I determined my tun dead space.  I filled above my screen and let it drain until it stopped and measure the volume.  To correct that I'm going to change my tun deadspace to .1875 gallons.  I can't really put an accurate reading until I've brewed again.  Once I've brewed, I'll be able to get an accurate reading of my tun deadspace.

I'll also change my efficiency to 68% for my next brew and see where I end up. 

You were extremely helpful!!

tom_hampton said:

I've seen many people measure this by filling the MLT with 1-2 gallons of water, and then draining it back out.  Whatever doesn't come out, they call "deadspace".  This is not correct, because it doesn't account for the volume of the tun that is filled by grain.  What many people don't consider is that much of the "deadspace" is actually accessible to grain.  So, the grain displaces MUCH of the wort in the "deadspace" in the mash. 

Click to expand...

Gohldamm good insight. Gohldamm Correct. Gohldamm Great Advice.

An update.  I've finally gotten a chance to taste this one.  It is really close to the Porter I tasted at Brews Brothers Microbrewery at the Silver Legacy Casino in Reno.  I'm quite pleased with it.  The few people that have tried it so far say that it is a great beer.