Partial boil for all grain?

[Jtd6628]

I took the terrapin rye clone recipe from this site and scaled it back to 5 gallons this requires a total of 9.77 Ibs of grain which can fit in my 16qt brew pot with 12.21qt of water for the mash according to the this formula. Volume of mash=Maxgrain(ratio water + .32). After I account for grain absorption at .1/lbs I am going to sparge with 6.7qt of water which will bring me to 15qt of wort to boil in my 16qt brew pot. After brewing 60 min that should leave me with 11qt of wort because of boil off. Now for my question
What harm will come form topping off with 9qt of water bringing me to my 5g batch.
This is my first attempt at not using any extracts I have done two mini mash that I mashed only 4lbs of grain then compensated with 5lbs of extract.
From everything I have read it says you can not do a partial boil with all grain HELP me understand why I can not do what I was thinking?
Thanks and good bye.

Here is the recipe I am according to iBrewmaster software
Terrapin Rye Clone 5G

Style: American Pale Ale OG: 1.048
Type: Partial Mash FG: 1.012
Rating: 0.0 ABV: 4.72 %
Calories: 157 IBU's: 49.00
Efficiency: 70 % Boil Size: 3.75 Gal
Color: 6.8 SRM Batch Size: 5.00 Gal
Boil Time: 60 minutes

Fermentation Steps
Name Days / Temp
Primary 14 days @ 67.0°F
Secondary 17 days @ 70.0°F
Bottle/Keg 42 days @ 70.0°F

Grains & Adjuncts
Amount Percentage Name Time Gravity
6.64 lbs 67.99 % Pale Malt (2 Row) US 60 mins 1.036
7.47 ozs 4.78 % Pale Malt (2 Row) US 60 mins 1.036
0.83 lbs 8.50 % Rye Malt 60 mins 1.029
2.49 ozs 1.59 % Rye Malt 60 mins 1.029
0.83 lbs 8.50 % Briess Munich 10L 60 mins 1.035
2.49 ozs 1.59 % Briess Munich 10L 60 mins 1.035
7.89 ozs 5.05 % Victory Malt 60 mins 1.034
3.12 ozs 2.00 % Honey Malt 60 mins 1.037

Hops
Amount IBU's Name Time AA %
0.80 ozs 34.13 Magnum 60 mins 14.00
0.83 ozs 8.75 Fuggles 30 mins 4.50
0.41 ozs 3.83 Goldings, East Kent 20 mins 5.00
0.41 ozs 2.29 Goldings, East Kent 10 mins 5.00
0.83 ozs 0.00 Cascade 0 mins 5.50
0.83 ozs Amarillo Gold 10 days 8.50

Yeasts
Amount Name Laboratory / ID
1.0 pkg American Ale II Wyeast Labs 1272

Additions
Amount Name Time Stage
0.83 oz Whirlfloc Tablet 15 mins Boil

Mash Profile
Medium Body Infusion In 60 min @ 154.0°F
Add 12.21 qt ( 1.25 qt/lb ) water @ 166.0°F

Carbonation
Amount Type Beer Temp CO2 Vols
5.28 oz Corn Sugar - Bottle Carbonation 68.0°F 2.50

Sent from my iPad2 using HB Talk

 

[erikhild59]

I think your efficiency will be very low if you don't sparge enough.If you only plan to top up with 9 qts , why not sparge with it instead and just catch it in another pot or two. You could even add some of your hops to it ... a partial boil will affect your hop utilization because the higher gravity wort won't absorb alpha acid as readily as lower gravity wort will.

 

[Jtd6628]

Will this work take a pre boil gravity reading and if under what software calls for compensated with DME durring the boil? Then top off during the boil to keep as much water in the boil as possible which will leave me with only having to top off with 1 gallon after the boil? I am afraid it will come out watery because of the top off post boil.

Sent from my iPad2 using HB Talk

 

[erikhild59]

Yes I think that would work, although I would recommend you add your (preboiled and cooled) top up water slowly and take gravity readings until you hit your target. Not sure if you need to add more hops or if your software compensates for higher gravity in the boil. Also, if you are mashing in a pot, a mashout will help max out your sparge efficiency.

 

[ayoungrad]

To address your original post... You CAN do a partial boil with all grain. The question is do you want to? And this seems to be a question that is debatable or at the least, unproven to my knowledge. And this is probably why you haven't received that many responses.

It might help to look at what happens during the boil. (This is mostly from Briggs)

Boiling in general does the following:

1. If mash-out was not performed, it deactivates enzymes and therefore stabilizes the type and amount of sugar in the wort.

2. It sterilizes the wort.

3. Proteins coagulate and interact with other wort substances including polyphenols and creates trub/break. That which precipitates in the boil is hot break and that which precipitates with cooling is cold break.

4. Hops substances are absorbed, isomerized, boiled-off or undergo reactions with other wort/mash substances.

5. Undermodified malt DMS will be boiled off.

6. The wort is concentrated.

I would imagine that much any possible effect of a lower boil volume and topping off is the result of substance concentration in the boil and pH of the boil and final wort. I honestly have no recollection of the remainder of Briggs' chapter to support what follows which is largely base on my educated opinion.

IMHO, I would be concerned that you would alter pH by topping off after the boil. And pH can absolutely affect flavor - a high pH (which is what you could get with topping off) causes a dulling of flavors.

Also, concentrations could affect hop utilization/oil evaporation rates. But many people state that this is more dependent on the amount of break. Considering this though, if the amount of break is the same regardless of wort concentration, this would not be much of an issue. On the other hand...

And if concentration factors and/or pH affects chemical interactions to a large extent, your hot and/or cold break could be affected. I do not know to what extent this could play a role.

So, basically, look at the things that happen during the boil and consider things that could possibly be altered by a lower volume. Obviously, hop utilization could be affected. And, as mentioned above, one of the main things is to insure that you do not cause an infection by topping off, which is #2. Other than that, #3 and #4 are the main players.

I have avoided topping off all-grain batches. My guess is that if you did this, you would get good beer but could probably make better beer if you did not top off. And you would save some money by using fewer hops.

 

[buckeye2011]

I did this exact method last night on my stove. Mashed, sparged and ended up with ~4.25 gallons of 1.045 wort pre-boil. I ended up using 1lb of DME to boost the gravity since I didn't think I could mash more than 9lbs of grain with that amount of water (turns out I probably can).

During the 60 minute boil, I boiled off almost 1 gallon of water which is close to what I would get on my propane burner outside. I can't imagine DMS will be an issue. I did have to adjust the hop schedule by boosting everything ~20%. Not a real big deal when I get hops for $1 an ounce.

Overall, everything went as planned and I expect it will make a fine beer. I'll let you know in about 5 weeks when its in the keg.

 

[Jtd6628]

[QUOTE=" I'll let you know in about 5 weeks when its in the keg.[/QUOTE]
please do I can manage another kit mini mash from AHS in the mean time but if you find you like the out come I will try the same thing with the terrapin clone.

Sent from my iPad2 using HB Talk

 

[dcp27]

From everything I have read it says you can not do a partial boil with all grain HELP me understand why I can not do what I was thinking?

you most certainly can, its just not common. ive done it a bunch and so hasn't revvy and others. you just need to compensate for a slightly lower hop utilization (like buckeye mentioned, bump your bittering add about 20%).

here's another thread that its already been talked about in: https://www.homebrewtalk.com/f13/post-boil-dilution-251823/