Recipe Formulation and Basic AG Process

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.

*sigh* post continued 'cause I don't know when to shut up...


Now, a little science to help dictate actions in various stages.

Mashing
A good rule of thumb for the thickness of your mash is 2.5L H20/kg grain – it’s all about the feel that you’re going for. A thicker mash means the enzymes and starches to be converted are closer together, but too thick a mash can leave you with dry grain (which then won’t be mashed, ‘cause you need water for everything to jazz) and the enzymes won’t be able to ‘move’ well enough to get to new starch. Too thin a mash causes the starch and enzymes to be too far away from each other, and you don’t get as much sugar out of it. Another thing to keep in mind is dead space (how much water sits at the bottom of your mash tun that you can’t get out, because of whatever filtration system you’re using) when figuring out how much water you should be adding to your mash tun.

The ‘Brewer’s Window’ for temperature (which has to do with gelatinisation, enzymes, and a couple other things) is 60-70°C. Higher (66-70°C) is more non-fermentable sugars (dextrins – also called residual sugars, they make beer ‘sweet’ and add to mouthfeel). Lower (60-64°C) is more fermentable sugars – more alcohol and a thinner beer. You will still get the same amount of sugar anywhere in the window – it’s just a matter of what shape the sugar is, and if the yeast can metabolise it. For strike temp, it's a matter of knowing your system, and a little bit of math. There are several different calculators online that will do the hard work for you.

A handy trick that I wish I'd known when I first started; if you leave 1L or so out of your total mash volume, then you can adjust your mash temp accordingly by adding hot or cold H20 to fix things up. To increase temp by even a few degrees, you'll want to add the full litre as hot as you can. Cold water works quickly and drastically - just a little at a time! If you hit your temp properly, then just make sure you add the extra L at the same temperature, and life will be happy!

Conversion of starch to sugar will occur within 45min, in my experience. I generally mash for 60min, just to be sure. A longer mash means more fermentable sugars, because you've given the enzymes more time to break everything down into smaller pieces. Anything past 90min is just being silly though, IMHO.

Brewing salt and liquor treatment is advanced stuff, if you want to geek out with your brewing. I put together a whole separate post on this in the BrewScience forum, and there are lots of really savvy brewers around here who know far more than I do, and can help you figure out what you want for your beer!


Sparging
Pretty much, this is to help dissolve the sugars and rinse them from the grain and to shut down the enzymes so they stop converting the starches (ie so you can keep some dextrins for taste and mouthfeel). You want to get the mash bed above 70°C to shut down the enzymes, but DON’T go above 80°C, ‘cause you start getting gross off-flavours. You really want to aim for between 70-75°C – any higher and you’ll dissolve more sugar (which is good) but you’ll also start to extract tannins, phenols, oxylates, more protein, and some other lovelies (which contribute to astringency, off flavours, and haze).

When you're starting your run off, you want to be gentle with your mash bed. The husks of the grain will create a filter for itself, which will let the wort run through in 'microchannels' but not take the grains with it! To do this, start your run off slowly and gently, and gradually increase the speed once the bed has compacted a little bit.

I recommend the vorlauf method regardless of what kind of sparging you use - this just means recirculating the wort to get rid of the worst of the particulate from the beginning of the runnings. To do this, just take a jug or something and drain off a good 2-4c of wort, until you stop getting big bits in it. Then, gently pour it back onto the top of the mash bed, being careful not to disturb the surface too much (remember those 'microchannels'!). Then you sparge.

In ‘batch’ sparging, you're draining off your first runnings (the liquor from your mash) and then dumping more hot water on top of that, mixing it around, letting it sit for a bit, and then draining off the new wort. Your main concern with this method is to get the whole thing to the right temp. Most of the sugars will be pulled out within 10-15min, so I wouldn't bother waiting longer than 20min tops. I also generally vorlauf between sparges as well.

The best way to figure out batch sparge volume IMO, is to figure out your desired pre-boil volume (more in 'Boiling'), subtract the volume of your first runnings from that, and then divide that volume in half and sparge twice. There are several calculators out there to help you figure out your strike temp for sparging.

Fly sparging, which I think is more hassle than it's worth for homebrewing (just my personal opinion!!!), is sprinkling the grains with hot water while slowly draining from the mash bed. This reduces mash exposure to air, which is suspected to lead to staling in the final product, and is also supposed to give you a clearer wort and more efficient mash (I'm not convinced on this, but that's what convention tells us!). In fly sparging, be SURE not to let your runnings drop below 1008, otherwise you'll start getting gross stuff.

To be perfectly blunt, I am still a beginner in many ways. There are some really great resources on the 'net for proper sparging methods - do a little research and figure out what makes sense/works for you!


Boiling
Boiling does lots of stuff – evaporate volatiles from the grain, convert alpha acids, precipitate proteins (hot break), and several other biochem reactions. Practically, all you need to know is that an agitated boil helps move everything along. Everything that needs to happen, should happen within 60min. Some like to boil longer in order to get more hot break out, but a vigorous boil should take care of that in a 60min boil.

Copper finings are stuff you can add to help pull out solids from your wort. Irish moss (AKA carageenen) is a charged particle that attracts protein and causes it to drop out. I generally add about 1tsp of Irish Moss 10min from the end of my boil. The theory is that once most of the proteins have precipitated the carageenen will help pull them out before you chill, but you can always experiment to see what you think works best.

If you figure out your boil off (how many litres you lose in your boil), you can calculate how much extra liquid you need to put through in order to get the proper final volume – otherwise, you’ll get super-concentrate beer (while fun, not necessarily always desired).


Chilling
This is to get your wort down to a temperature the yeast will be happy with. A brewer's responsibility is to please his yeast. Also, more protein will precipitate out of your wort once it's chilled - this is called 'cold break', and removing it will also help with clarity in the the finished product. You want to chill your wort as fast as possible, to prevent several reactions that will occur in the mid-temperatures and create icky flavours (eg. DMS, a 'cabbage' taste, is often caused from a slow chill after boil).

My system of chilling is pretty basic - a coil of copper connected to a couple hoses. One side is hooked up to a tap, the other down the drain. Run cold water (as cold as you can get!) through the copper until your wort is at the right temp (20-25C). Remember to sterilise your thermometer when you check temp now - ALL PROCESS' AFTER THE BOIL NEED TO BE SUPER SQUEAKY CLEAN!

Again, there are lots of different ways transfer your wort - find what works for you. Personally, I sterilise a sive and a funnel, and pour my wort from the boil pot through the sive and funnel into my primary fermenter (which is a glass carboy). Chilling in the boil pot and straining through the hops has the added bonus of removing both the hot and cold break.

There are some homebrewers who whirlpool instead- you'll have to ask them how they do it, 'cause I don't have a clue!


Fermentation
It’s all about yeast strain and temperature – try and keep your temp nice and consistent (if you’re having trouble with stuck fermentation, try and keep your carboy off the ground, or even stick it in a bathtub with water to regulate the temp). Too high a temperature and you get weird flavours, too low and the yeast falls out (flocculates) too soon. You can choose a special yeast depending on your style, or you can just stick with dry yeast. Either choice has it's advantages and disadvantages, and it's such a big topic that I won't go any further with it here.


Conditioning/Packaging
If you are bottle conditioning, there is a trick you can use to avoid priming. Take a little bit of your wort and put it in a separate container (maybe 250-500ml, in a plastic bottle) and add an excess of yeast. This is called your 'forcings', and the gravity will drop much faster with this super-fermented wort. Then you check the gravity of your forcings, which is where your beer will ferment fully out to (FG). All you have to do is chill your beer (rack to secondary if you like, and put it somewhere COLD) at 2 degrees ABOVE your FG, and that will act as your priming in the bottle instead of adding sugar for the yeast to carbonate with. Makes bottling just a little easier.


I will say once more that I'm still a beginner in many ways - I've only been brewing for about a year. If I've said something that contradicts what you know, please tell me - I want to learn!

Damn, Skippy. If my brother was this generous and considerate, I'd be running my own brewery by now. You have a very lucky Bro.

Skippy?

To be fair, my bro already knows what he's doing with brewing. I just finished a course in brewing technology though, so he wanted to pump me for a little more info.

Hey, just a quick thanks for the juice loved the stuff on mashing / sparging