Question Regarding Boil Gravity

[mateostojic]

Gentlemen,

I am a reasonably new brewer and having done one kit brew and one kit'n'bit brew i cant wait to get on to extract.
So i have been doing a fair bit of reading trying to understand the whole process and i think i am getting on top of it.
I have one question regarding boil gravity.
I understand that we want our boil gravity to be 1.040 for consistency and good hop optimization and accurate IBU calculation.


I know that dme typically yields 40pts/lb/gal and that based on that the rule of thumb is 100grams of dme to every litre of water to achieve 1.040 boil gravity.

Most extract recipes, esp the ones that i am looking at, use approx 250g grain steeped in 2-3L and rinsed so that in the end you end up with around 4-5L boil volume before you start adding hops.

What i would like to know is a rule of thumb (or a figure in pts/lb/gl,or metric) for grain so that i can know that my boil gravity is in the area of 1.040 before I start adding hops, which will give me piece of mind when i am calculating my IBU.

 

[buttersd70]

The higher the boil volume, the less impact it will have, to the point where it can effectively be excluded. For lower boil volumes, it could be taken into account, and worked out mathematically....the extent of how accurate you want to be with it really depends on how anal you want to get with it.

The actual efficiency of a steep of spec grains relies on several factors, but if you were to use an efficiency of 40-50%, that would likely be fairly close. In a nutshell, it works out to, as a generalisation, ~5 points of gravity per 250g per 5L. Subject to a very big "ish" factor.

 

[raven19]

Keep in mind 1040 Gravity Wort is not the be all and end all, it can be higher or lower depending on preference, beer style, etc.

But to get 1040 Wort from Grain - this will depend on your efficiency, system, etc.

However by a quick Beersmith calc, I get 1 kg of Pale Malt to 5.5L of boiled wort (this assumes a 6.3L Preboil Volume).

So in the order of 1kg to 6-ish L should get you about there. This will depend on grain type, efficiency, sparge method, etc...

 

[Dazza_devil]

I use this,

http://www.aussiehomebrewer.com/forum/inde...9655&st=120


Cheers.

 

[buttersd70]

yep, forgot about ians sheet. It takes it into account iirc.

 

[Pennywise]

If you want to know going by your method and system, I'd suggest steeping some grain and take a gravity reading of it (at the specified temp for your hydrometer). That way you know exactly how you and your method reach a certain gravity or PPG. As long as you keep the same method & system, you'll be pretty spot on with your calcs. Me, I just whack it into Beersmith and use more hops if I have to, to a certain point anyway, I don't mind using 10-15g more in a batch for bittering if need be and it makes my brew day easier.

 

[mateostojic]

The actual efficiency of a steep of spec grains relies on several factors, but if you were to use an efficiency of 40-50%, that would likely be fairly close. In a nutshell, it works out to, as a generalisation, ~5 points of gravity per 250g per 5L. Subject to a very big "ish" factor.
[/quote]

So i would have to use 1kg of grain for 5L boil to get 1040 wort. Most extract recipes use 250g of grain. That means that i should be adding in some lme before the hops (or dlme depending on recipe)


Good point 79, I forgot about practical testing. Got too caught up in calcs. I will measure my wort for sure. Cheers

 

[buttersd70]

So i would have to use 1kg of grain for 5L boil to get 1040 wort. Most extract recipes use 250g of grain. That means that i should be adding in some lme before the hops (or dlme depending on recipe)

That's correct, you would need to add some of the extract to get close to a 1040 wort. Unless you were using a ridiculously high amount of specialty grains.