High OG in relation to grist coarseness

[Johnny_Ds]

A have a couple of questions. I'm going to try to be thorough in my descriptions and variables so this might be longer than normal.

I've been brewing for two years. This past summer, after getting all my gear bought and set up, I went to AG brewing. My first two brews were from pre-ground kits. My last two have been from recipes where I ground the grain myself. My grind was significantly finer than the grind I got from the kits. I can't remember the exact roller spacing, but it's he first mark (of the three) on the Cereal Killer mill. The finest setting. I know this isn't what I've seen recommended on this forum and elsewhere, but I really liked the grind I was seeing... it had good endosperm reveal, but didn't look like flour either.

The first recipe I did (with my own grind) last month was a Helles, yesterday I did an Oatmeal Stout.

My recipe stated that my preboil SG should be 1.047, my OG should be 1.055.

My grain bill for the stout was 25.8 lbs for a 10 gallon batch. The calculator I used said I would need 9 gallons of water for the mash. The mash temp was 154F. The recipe suggested I mash for 90 minutes to fully convert the oatmeal. At the 90 minute mark my iodine test showed incomplete conversion. I also noted that the mash had completely soaked up my mash water so I added an additional gallon of 160F water. I gave a gentle stir and waited 25 mins and the conversion test showed positive so I began vorlaf via recirc.

Once I had clear runnings I began collecting wort in my kettle whilst sparging. This process took approximately 1 hr. At the one hour mark I was still getting ink dark runnings from my stout. The recipe called for 14 gallons of preboil wort. My runnings were still very dark when I ran out of sparge water. I had 16 gallons of wort in my kettle at this point. My preboil SG was 1.057 at this point.

I had 16 gallons of wort that was already significantly higher than my preboil SG was supposed to be, even higher than my OG was supposed to be. I decided to boil down until I got to just a little more than 11 gallons. Needless to say this took some time. My OG ended up being 1.068... way off from the 1.055 it was supposed to be.

Here in lies my biggest question.

** Should I have boiled for the hour and chilled my wort regardless of the amount (gallons) and collected based solely on my OG numbers?

My fear was that the flavor would be off and continued to boil, understanding that I would end up with a probable higher ABV. I didn't want a beer with the target ABV but with an incorrect flavor profile.

** Am I getting crazy efficiency by grinding finer? If I based my boil soley on my OG I would have had easily a 15 gallon batch.

I found this experiment comparing grind coarseness and the resulting beer... http://brulosophy.com/2015/11/23/mind-the-gap-course-vs-fine-crush-exbeeriment-results/

Note: I'm using the SS Brew Tech 20 gallon Mash Tun. It works like a charm, keeps temp and I've never had a stuck sparge.

This same thing happened with my Helles last month, but it wasn't to this degree. I ended up with 14 gallons of wort when I hit my OG with that batch and I again decided to boil down to 11 gallons, cool, transfer and pitch. That particular batch I bottled yesterday as well. My initial taste test didn't yield any noticeable off flavors or overly strong flavors in the Helles... in fact if anything it tasted a bit weak, though not by much.

Thoughts comments?

 

[mredge73]

Your calculator is broken...

What brewhouse efficiency are you using when calculating your recipes?
Your efficiency is obviously much higher with your new mill. You need to adjust accordingly in you calculations.

I don't know what your recipe is but at 70% efficiency 25.8 lbs of 2-row would yeild an OG of 1.067 in a 10 gallon batch.
Your efficiency is likely higher than 70%; some people have built systems that can get it north of 80%.

Note that brew house efficiency is not the same as mash conversion efficiency. Most people can get +95% in conversion efficiency, you sound like you are having a little trouble here as well.
When using oatmeal use rolled oats or instant oatmeal as these convert better.

More importantly you have some volume marks to work on. How much Oatmeal did you use to soak up all that water?
You used 9 gallons for the mash; grain should have absorbed ~3.5 (~.14 gallons per lb) leaving you with first runnings around 5.5 gallons.
In other words, you shouldn't have had to add more water.
Boil evaporation is 1.25 gal/hour for me; can't be much more for you. Sparge water would need to be 5.75 gallons; add this to the first runnings for a total boil volume of 11.25 gallons.
If you account for hop absorption you may want a little more volume, maybe a half gallon more.
But staring the boil at 16 gallons or even 14 gallons doesn't make any sense. These numbers are way out of the park.

 

[Johnny_Ds]

Thanks for the input.

That said... given my situation, should I have boiled it down like I did and overshoot the OG or should I have boiled for the hour and had a larger batch than I anticipated?

Here's the grain bill

18.8 lbs English Pale Malt
2.0 lbs Flaked Oats, toasted
1.5 lbs Chocolate Malt
1.5 lbs Victory Malt
1.0 lb Crystal 80
1.0 lb Black Roasted Barley

This is the calculator I use: http://www.brew365.com/mash_sparge_water_calculator.php

 

[IslandLizard]

Thanks for the input.

That said... given my situation, should I have boiled it down like I did and overshoot the OG or should I have boiled for the hour and had a larger batch than I anticipated?

Here's the grain bill

18.8 lbs English Pale Malt
2.0 lbs Flaked Oats, toasted
1.5 lbs Chocolate Malt
1.5 lbs Victory Malt
1.0 lb Crystal 80
1.0 lb Black Roasted Barley

This is the calculator I use: http://www.brew365.com/mash_sparge_water_calculator.php

That's a mash calculator, I always use that one on brew day. What did you put in as your water/grain ratio? Many of us use 1.5 quarts of water per pound of grist. That is unless the mash tun is too small to hold that volume, then we need to drop it. I wouldn't go below 1.1, and that's darn thick.

You also need a good recipe/brewhouse calculator so you don't overshoot your gravity, as you just did. It then takes 2 or 3 brews to nail your temps and numbers.

When grabbing a recipe off the net or elsewhere, you usually don't have a clue what efficiencies that recipe is based on. So plug it into your recipe formulator and check your numbers. Obviously for your system you had too much grist for the given volume.

If the difference after boiling is no more than 2-5 points* from what was calculated I tend to let it be as is, but make a note to compensate for next time. In your case, I would probably live with the higher gravity for this time, unless I had enough spare space in the fermentation vessel to thin it down a little.

*Being off more than 5 points has become a very rare occurrence, and would be due to a gross error somewhere.

 

[mredge73]

That water volume calculator isn't much different than what I use. Using the built in constants I still only get 12.15 gallons boil volume.

In your situation you should have boiled the normal 60-90 minutes that you planed your hop schedule to. Over boiling messes up your hop profile; longer boils emulsifies more AA while precipitating flavor and aroma compounds.
Then split between fermentors what you have left.

I punched your recipe in brewmate for a 11 gallon batch, looks like you hit ~80% brew house efficiency.
That is fantastic if you can keep it up, best I can consistently do is 73%. Use this info when planning your next batch.

 

[Johnny_Ds]

So, what I'm gathering from the posts here is that I should have stopped when I met my OG.

I understand that the calcs were off which probably had do with my grind and brewhouse efficiency.

The good news is I have a large number of fermenters from 2.5 gallons up to 12 gallons. I could have easily accommodated the 15 or so gallons I had when I hit my OG.

Also, I saw what was happening and held off on my hops additions, calculated how long before I would hit my target volume and dosed accordingly, so that should be fine. I'm only wondering about the overall flavor profile now. It seems it will be different than what was expected.

As for the water to grain ratio, I used the default on the calculator which is 1.33. My mash tun and kettle both are 20 gallons.

It sounds like I boiled away 4-5 gallons of good beer.......

 

[mredge73]

20 gallon kettle shouldn't boil any more than 1.5 gallon per hour unless you are spilling over.
Punch that in as your evaporation (7.5%) on the calculator. I use 1.44 as my water to grain ratio, 1.33 should be just fine.
On the overall flavor profile it will be a tad bit sweeter with more abv. The long boil increases hop oil emulsion but weirdly decreases perceived bitterness like a FWH addition.
This will bring the malt forward in a already malt forward beer. You will also have higher alcohol, this will cover up some of the sweetness. I got a feeling that it will still turn out terrific.