TheChemist
Well-Known Member
So, I put this together for my brother, who wanted some details on his basic AG process, and I figured I may as well add a bit more to it, and post it here as well. I hope this helps someone, and please ask for clarification if I don't make sense! (ADMIN: wasn't sure where to put this - please move if you can think of a better place for it)
The basic process of brewing goes (if we assume our raw materials are prepared for us - ie malting/kilning/milling grain, growing/drying hops, etc) goes something like this:
Mashing>>Separation/Sparging>>Boiling>>Chilling>>Fermenting>>Conditioning>>Packaging
Mashing is to convert starch in the grain to sugar. Separation is to get the sugar solution (wort) out of the grains. Boiling is to sterilise, stabilise, and condense the wort. Chilling is to make the wort ready for pitching (adding) the yeast. Fermenting (aka primary) is to let the yeast make sugar into alcohol. Conditioning (aka secondary) is to let the yeast drop out, and to help the beer stabilise and improve flavour development. Packaging is for storage/use. Note: conditioning and packaging can often be in the same step, eg. bottle or cask conditioning.
Everything before the boil is often called 'hot side', and after the boil 'cold side'. Hot side should be clean, but remember that you're boiling the wort, so don't make yourself crazy. After the boil, however, be sure that everything is sterilised - bacterial infection can make a fantastic beer unpalatable.
First, recipe formulation.
Grain Bill
Mashing is all about getting out as much of the theoretical amount of available sugars in the grain as possible. Keep in mind that you’re NOT getting ALL of the sugar out of the grain, so you need to add extra grain to account for the inefficiency (most homebrews are anywhere from 60-80% - I'd say start at 70%, and then calculate your own after you've used your system a few times).
If we think of gravity (ie sugar concentration) in degrees (°), and volume in litres (L), then the unit we want to use for calculations is in litre degrees (L°). The amount of available sugar in a grain is expressed in L°/kg. You can ask your brew store for the extract of the malt, and they SHOULD have it – if not, just use 300L°/kg for pale malts, 260-290L°/kg for coloured (darker malts have less sugar because they've been kilned longer).
The ratio that relates ABV to gravity (degrees) is called the f-factor, and it changes depending on the ABV (3.3-4.6%=0.129, 4.6-6.0%=0.130). The general rule is supposed to be that 4/5 of the sugars you get are fermentable – this varies depending on mash temp (and grain bill, and system, and yeast strain, etc) but applies for around 65C. More on this in the 'Mashing' section.
The residual sugars (AKA Final Gravity (FG) or dextrins) are the saccharides that are too big for the yeast to ferment. If there’s a specific FG that you want (for mouthfeel and 'sweetness'), you can just use that instead of the fraction (eg, you want a FG of 1010 for a thicker ale, so you add fermentable sugars to that, instead of calculating out the 5/4 thing).
Calculations go like this;
1. Chosen ABV ÷ f-factor = degrees of fermentable sugars (°)
2. Degrees of fermentable sugars (°) x 5/4 = original gravity (°) OR
Degrees of fermentable sugars (°) + desired FG (°) = original gravity (°)
3. Original gravity (°) x volume (L) = total sugars (L°)
4.Total sugars (L°) x efficiency for your system (for 70%, multiply by 100/70) = recipe sugar (L°)
5. Recipe sugar (L°) x % of grain in recipe = % of recipe sugar per malt (L°)
6. % of recipe sugar (L°) ÷ potential of malt (L°/kg) = kg of malt
So for an example recipe, I want a 4.0% beer, with 90% pale, 8% crystal, and 2% chocolate and my homebrew system mashes at 70% efficiency
1. 4.0%ABV ÷ 0.129 = 31° (for fermentable sugars)
2. 31° x 5/4 = 39° (to add the non-fermentable sugars)
3. 39° x 19L = 741L° (theoretical sugar for recipe)
4. 741L° x 100/70 = 1059L° (practical sugar for recipe)
5. 1059L° x 90% = 953L° (for pale)
1059L° x 8% = 85L° (for crystal)
1059L° x 2% = 21L° (for chocolate)
6. 953L° ÷ 305L°/kg = 3.12kg (for pale)
85L° ÷ 268L°/kg = 0.32kg (for crystal)
21L° ÷ 265L°/kg = 0.08kg (for chocolate)
To figure out efficiency for future batches, take your actual OG and multiply it by your final volume. Then, divide that figure by your original sugar total.
For this example brew, let’s say I got an end brew of 20L at an OG of 1040. That’d be 18.5 x 40 = 800, and then 800/1059 = .7554, so 75.5% efficiency in mash conversion. Once you’ve done this for a couple of your brews you’ll begin to get an idea of the efficiency of your kit, and then you can adjust your recipes accordingly.
As for actual percentages for malt, there are lots of good resources on what malts create which flavours and characteristics in beer. However, here are a couple things that I keep in mind when making a recipe;
- You need enough pale malt to provide the enzymes to convert the mash, so don't use TONS of adjunct malts
- Wheat and flaked barley will add to head retention and mouthfeel, but I'd only use 5-10% of them in a recipe, otherwise you'll start to get issues with haze and/or stuck mashes. Obviously, that rule changes for a wheat beer.
- I suggest starting with lower percentages of adjunct and working your way up. Better to have a lighter stout than you expected, than to feel like you're drinking burnt grains.
-Have fun and experiment!
Hop Schedule
Hops are for bitterness, taste, and aroma. The hops you add at the beginning of the boil are for bitterness, at the end for aroma/taste, and in the middle for some combination of the two. There’s really no good way of figuring out your utilization of hops for the middle addition, so it’s easiest to just do bittering and aroma. Boiling converts alpha acids to iso-alpha acids, which is the bitter stuff - the conversion is called isomerisation. This works best in an alkaline solution, so the highest theoretical utilisation in our acidic wort is around 45%. During fermentation some of the iso-acids are absorbed by protein and yeast, and you rarely get full utilisation to begin with, so the actual percentage is usually closer to 25%.
The essential oils that create hop aroma will boil off within 5min, and the other flavours from 10-20min, so I’d suggest tossing in your aroma hops and let it go for 2-3min, and then turn off your boil.
Calculations:
[Volume of batch x IBU x 10 units (this is just to balance out the numbers)] /
[Alpha acid % of hop x utilization (25%)]
So for this beer I’m making in theory, I want 28IBU, and the a.a. on my hops is 6%
(19L x 28IBU x 10) / (6.0% x 25%) = 35.5g of hops for the bittering
Like I said, later additions screw with your utilization, but you can probably say that middle additions (20-30min) are around 12% or so, and aroma barely use 1% (if!). Aroma additions are usually around 150-300% of bittering hops in weight.
The basic process of brewing goes (if we assume our raw materials are prepared for us - ie malting/kilning/milling grain, growing/drying hops, etc) goes something like this:
Mashing>>Separation/Sparging>>Boiling>>Chilling>>Fermenting>>Conditioning>>Packaging
Mashing is to convert starch in the grain to sugar. Separation is to get the sugar solution (wort) out of the grains. Boiling is to sterilise, stabilise, and condense the wort. Chilling is to make the wort ready for pitching (adding) the yeast. Fermenting (aka primary) is to let the yeast make sugar into alcohol. Conditioning (aka secondary) is to let the yeast drop out, and to help the beer stabilise and improve flavour development. Packaging is for storage/use. Note: conditioning and packaging can often be in the same step, eg. bottle or cask conditioning.
Everything before the boil is often called 'hot side', and after the boil 'cold side'. Hot side should be clean, but remember that you're boiling the wort, so don't make yourself crazy. After the boil, however, be sure that everything is sterilised - bacterial infection can make a fantastic beer unpalatable.
First, recipe formulation.
Grain Bill
Mashing is all about getting out as much of the theoretical amount of available sugars in the grain as possible. Keep in mind that you’re NOT getting ALL of the sugar out of the grain, so you need to add extra grain to account for the inefficiency (most homebrews are anywhere from 60-80% - I'd say start at 70%, and then calculate your own after you've used your system a few times).
If we think of gravity (ie sugar concentration) in degrees (°), and volume in litres (L), then the unit we want to use for calculations is in litre degrees (L°). The amount of available sugar in a grain is expressed in L°/kg. You can ask your brew store for the extract of the malt, and they SHOULD have it – if not, just use 300L°/kg for pale malts, 260-290L°/kg for coloured (darker malts have less sugar because they've been kilned longer).
The ratio that relates ABV to gravity (degrees) is called the f-factor, and it changes depending on the ABV (3.3-4.6%=0.129, 4.6-6.0%=0.130). The general rule is supposed to be that 4/5 of the sugars you get are fermentable – this varies depending on mash temp (and grain bill, and system, and yeast strain, etc) but applies for around 65C. More on this in the 'Mashing' section.
The residual sugars (AKA Final Gravity (FG) or dextrins) are the saccharides that are too big for the yeast to ferment. If there’s a specific FG that you want (for mouthfeel and 'sweetness'), you can just use that instead of the fraction (eg, you want a FG of 1010 for a thicker ale, so you add fermentable sugars to that, instead of calculating out the 5/4 thing).
Calculations go like this;
1. Chosen ABV ÷ f-factor = degrees of fermentable sugars (°)
2. Degrees of fermentable sugars (°) x 5/4 = original gravity (°) OR
Degrees of fermentable sugars (°) + desired FG (°) = original gravity (°)
3. Original gravity (°) x volume (L) = total sugars (L°)
4.Total sugars (L°) x efficiency for your system (for 70%, multiply by 100/70) = recipe sugar (L°)
5. Recipe sugar (L°) x % of grain in recipe = % of recipe sugar per malt (L°)
6. % of recipe sugar (L°) ÷ potential of malt (L°/kg) = kg of malt
So for an example recipe, I want a 4.0% beer, with 90% pale, 8% crystal, and 2% chocolate and my homebrew system mashes at 70% efficiency
1. 4.0%ABV ÷ 0.129 = 31° (for fermentable sugars)
2. 31° x 5/4 = 39° (to add the non-fermentable sugars)
3. 39° x 19L = 741L° (theoretical sugar for recipe)
4. 741L° x 100/70 = 1059L° (practical sugar for recipe)
5. 1059L° x 90% = 953L° (for pale)
1059L° x 8% = 85L° (for crystal)
1059L° x 2% = 21L° (for chocolate)
6. 953L° ÷ 305L°/kg = 3.12kg (for pale)
85L° ÷ 268L°/kg = 0.32kg (for crystal)
21L° ÷ 265L°/kg = 0.08kg (for chocolate)
To figure out efficiency for future batches, take your actual OG and multiply it by your final volume. Then, divide that figure by your original sugar total.
For this example brew, let’s say I got an end brew of 20L at an OG of 1040. That’d be 18.5 x 40 = 800, and then 800/1059 = .7554, so 75.5% efficiency in mash conversion. Once you’ve done this for a couple of your brews you’ll begin to get an idea of the efficiency of your kit, and then you can adjust your recipes accordingly.
As for actual percentages for malt, there are lots of good resources on what malts create which flavours and characteristics in beer. However, here are a couple things that I keep in mind when making a recipe;
- You need enough pale malt to provide the enzymes to convert the mash, so don't use TONS of adjunct malts
- Wheat and flaked barley will add to head retention and mouthfeel, but I'd only use 5-10% of them in a recipe, otherwise you'll start to get issues with haze and/or stuck mashes. Obviously, that rule changes for a wheat beer.
- I suggest starting with lower percentages of adjunct and working your way up. Better to have a lighter stout than you expected, than to feel like you're drinking burnt grains.
-Have fun and experiment!
Hop Schedule
Hops are for bitterness, taste, and aroma. The hops you add at the beginning of the boil are for bitterness, at the end for aroma/taste, and in the middle for some combination of the two. There’s really no good way of figuring out your utilization of hops for the middle addition, so it’s easiest to just do bittering and aroma. Boiling converts alpha acids to iso-alpha acids, which is the bitter stuff - the conversion is called isomerisation. This works best in an alkaline solution, so the highest theoretical utilisation in our acidic wort is around 45%. During fermentation some of the iso-acids are absorbed by protein and yeast, and you rarely get full utilisation to begin with, so the actual percentage is usually closer to 25%.
The essential oils that create hop aroma will boil off within 5min, and the other flavours from 10-20min, so I’d suggest tossing in your aroma hops and let it go for 2-3min, and then turn off your boil.
Calculations:
[Volume of batch x IBU x 10 units (this is just to balance out the numbers)] /
[Alpha acid % of hop x utilization (25%)]
So for this beer I’m making in theory, I want 28IBU, and the a.a. on my hops is 6%
(19L x 28IBU x 10) / (6.0% x 25%) = 35.5g of hops for the bittering
Like I said, later additions screw with your utilization, but you can probably say that middle additions (20-30min) are around 12% or so, and aroma barely use 1% (if!). Aroma additions are usually around 150-300% of bittering hops in weight.