Water Calculations vs Density Measurements

[matota85]

Hi guys,

My name us Matias, from Buenos Aires, Argentina, and Ive just registered myself.

My experience with home brewing is very limited (just 1 batch, and still waiting for it to be done), but I find it to be a very interesting world!

My doubt is the following:

When you so all de math for the water calculations, the is no input for which is the Original Gravity you are aiming for, instead is all based in different parameters related to water losses and grain weight.

So, how is the balance you must deal with while brewing? Is the OG assumed to be correct when you use the 1:3 relation for the Strike Water?

If the OG is the density you wanna target after the boil, how can you be sure you will get there and you wont be below or over it?

Hope Im being clear,

Thanks for your help,
Mato


PS: Just for double checking, this are my water calculations for a 10L batch:

Mashing

Grain Weight 3 Kg
Mash Thickness 3 Lts/Kg
Grain Absortion 1 Lts/Kg
Absortion Loss 3 Lts
Mash tun to
boiling kettle loss 0 Lts

Boiling

Boiling Time 1 hr
Evaporation Rate 2,76 Lts/hr
Wort Shinkage 4%
Boiling Loss 2,76 Lts
Shrinkage Loss 0,73 Lts
Boiling kettle to
fermenter loss 2 Lts

Fermenting

Fermenter to
bottling loss 2,75 Lts

Water Volumes

Strike Water 9 Lts
Sparge Water 9,24 Lts
Pre-Boil Water 18,24 Lts
Post-Boil 14,75 Lts
Fermenter 12,75 Lts
Batch Size 10 Lts

Total Water: 18,24 Lts

 

[MaltMaker]

OG is the specific gravity targeted at the start of fermentation or after the boil.

To ensure you hit the target OG you need to be familiar with and adjust your system.

For example, if you make a beer and target 1.050 OG but actually have 1.060 then perhaps you used too much malt or maybe you recently started adjusting your water or boiled off to much.

If you make a beer and target 1.050 OG but actually have 1.040 then perhaps you didn't use enough malt or maybe your ending volume is greater than desired.

There are many reasons for over or under shooting your OG, the key is to become familiar with your system and process, making adjustments as necessary.

Knowing your boil off volume is of great help in this regard and also getting and keeping a consistent crush.

 

[matota85]

OG is the specific gravity targeted at the start of fermentation or after the boil.

To ensure you hit the target OG you need to be familiar with and adjust your system.

For example, if you make a beer and target 1.050 OG but actually have 1.060 then perhaps you used too much malt or maybe you recently started adjusting your water or boiled off to much.

If you make a beer and target 1.050 OG but actually have 1.040 then perhaps you didn't use enough malt or maybe your ending volume is greater than desired.

There are many reasons for over or under shooting your OG, the key is to become familiar with your system and process, making adjustments as necessary.

Knowing your boil off volume is of great help in this regard and also getting and keeping a consistent crush.

Ok, then the correct way to brew would be to start with the water calculations and check your OG post boil to see if you are ok

In the case you over/under shoot your target original density, say 1045, is there any correction you can implement or is already too late and maybe next time adjust you sparge water in order to correct this?

Checking density is only informative or you can correct on the go accordingly?

 

[MaltMaker]

If you undershoot you can use some DME (Dry Malt Extract) to raise the gravity to the desired value.

If you overshoot you can dilute using boiled and cooled water to lower the gravity to the desired value. Of course this increases the volume.

 

[matota85]

If you undershoot you can use some DME (Dry Malt Extract) to raise the gravity to the desired value.

If you overshoot you can dilute using boiled and cooled water to lower the gravity to the desired value. Of course this increases the volume.

And you would do this in the post boil step, am I right?

 

[jaspass]

Many tools (like Beersmith) will offer a pre-boil gravity calculation. This is the best starting point to see if you are on track to hitting your starting gravity when your boil is complete. If you are coming in too low, you have several options to correct. You can add some DME or other sugar (depending on style) to the boil, you can boil a little longer to evaporate more water, or you can just accept a lower gravity level. If you are coming in too high then you can add some water, boil a little less, or again just accept a higher gravity (generally I'm fine with a little more ABV). There are lots of options to correct when monitoring the gravity pre-boil and along the way.

 

[matota85]

Many tools (like Beersmith) will offer a pre-boil gravity calculation. This is the best starting point to see if you are on track to hitting your starting gravity when your boil is complete. If you are coming in too low, you have several options to correct. You can add some DME or other sugar (depending on style) to the boil, you can boil a little longer to evaporate more water, or you can just accept a lower gravity level. If you are coming in too high then you can add some water, boil a little less, or again just accept a higher gravity (generally I'm fine with a little more ABV). There are lots of options to correct when monitoring the gravity pre-boil and along the way.

Thanks for the info.

Right now im not using any software, I made my own spreadsheet in order to understand all the calculations involved as well as the process, I guess I still need to figure out the calculation for the OG estimation.