PenSans Brewery - Processes

Brewing Processes

SPARGING

OK, so you've got yourself an excellent mash on the go

the mash section

HOW MUCH SPARGE LIQUOR WILL I NEED ?!

Estimating this isn't so difficult if you just acknowledge the fact that some of the mash liquor gets stuck in the grain and never comes out, some of the wort disappears by evaporation during the boil stage and some wort gets stuck beneath your mash tun's false bottom. So, here are a couple of tables that try to assist you with these calculations. I know that they may look long & detailed at first glance (they are !) but the maths is very simple and those of you with access to a spreadsheet program should already know what to do with it !

TABLE 1 : Backwards from the Fermentor to the Boil

Let's start by looking backwards from your fermentor to the start of the boil . . . perfect sense eh !

Question	Answer	Code	Comment
How much wort do I want to see in my fermentor ?	23 litres	A	Remember to leave some room for the yeast to rise and fall
Does any wort get lost in the chiller ?	0 litres	B	Depends on your setup
Amount of wort that should enter your chiller stage	23 litres	A + B	Simple maths !
Does any wort remain in the boiler after run off, you know, mixed up with hops and trub ?	3 litres	C	Depends how well the hops etc settle as well as how high the exit pipe is from the bottom of the boiler
How much should I have at boil end ?	26 litres	A + B + C	More simple maths
What's my evaporation rate during the boil ?	2 litres per hour	R	Depends on how intense you run the boil
How long do I boil for ?	1.5 hours	t	Don't compromise . . . t = 1.5 OK ?!
So how many litres do I typically lose during the boil ?	3 litres	D	R x t = 3
How much wort should I have at boil start ?	29 litres	A+B+C+D	Hope you're keeping up with the maths here !?

So your boiler should be at least 32 litres in order to be able to handle a start volume of 29 litres.
A 25 litre boiler therefore is asking for size problems. Ask me, I know, I had one ! I used to collect 25 litres of run off from the sparge, put 22 litres into the boiler and then top the other 3 litres up during the boil, making sure that the last addition was at least 20 minutes before boil end. But this really isn't a good plan. I also used to see the wort boil down to 23 litres at boil end and then add two litres of boiling water from a kitchen kettle as I turned the power off but again, its all a compromise on getting a decent sized boiler in the first place, it really minimises process hassles on the day if everything's the right size.
So the next step is to find out how much of the wort comes out of the mash step itself and how much of it from the addition of sparge liquor . . . onto table 2.

TABLE 2 : Backwards from the Start of Boil to the Mashing & Sparging steps

Backwards again . . . but its easier to calculate the first time out !

Question	Answer	Code	Comment
How much grain do you have in your mash tun ?	5 kg	M	Now what does this have to do with anything you ask ?!
How many litres of mash liquor do you add per kg of grain ?	2.3 litres per kg	X	For a single temperature infusion mash this is typical
Is any wort lost beneath the false bottom of the mash / lauter tun ?	2 litres	Y	Depends on your equipment design
So how much mash liquor originally goes into your mash tun ?	13.5 litres	(M*X)+Y	Not quite MC² but getting there
Wort gets stuck in the grains but at what rate ?	0.57 litres per kg		Estimate as 0.57 litres per kg of grain until you work out something different !
So how much of the wort gets stuck in your mash ?	2.85 litres	Z=0.57*M	This is the liquid that makes the grain all squelchy after the mash has run totally dry
So how much of the liquor in the tun at the start of the mash actually gets out to the boiler ?	8.65 litres	Not Much !	13.5 (what goes in) - 2.85 (lost in the grain) - 2.0 (lost space)

TABLE 3 : Let's Summarise & Finish Off !

Question	Answer	Comment
The required boil-start wort volume was :	29 litres	See table 1 above
The volume of wort obtained from the mash liquor itself :	8.65 litres	See table 2 above
Hence the volume of sparge liquor required :	20.35 litres	i.e. the difference !
The volume of sparge liquor that gets stuck beneath the tap of the hot liquor tank	2 litres	Something always get stuck unless you can tip the thing but tipping vats of hot water ain't too clever !
Required volume of the hot liquor tank in order to supply enough sparge water	22.35 litres	OK, so round this up to 23 litres
What volume of hot liquor tank is required to supply all mash and sparge liquor from one vessel ?	37 litres	i.e 23 + 13.5

Any questions ?!

CONDUCTING THE SPARGE

So you have a great mash and 23 litres of sparge liquor ready. Most books tell you to heat the sparge liquor to 75°C but this assumes that you have mashed out, meaning that at mash-end you have infused some hot water to get the mash temperature up or that you have directly heated your mash to get there. However, most people struggle to do this as they either use plastic buckets or they have precious little room left in which to add extra liquor after the end of the mash. However, if possible, add very hot water and mix in quickly, say boiling water that is quickly mixed in to the mash. Be careful not to dig too deep though or you will destroy the nice filter bed structure down next to the false bottom.

So, assuming you have mashed out, sparge liquor at 75°C is great. As I don't routinely mash-out (compromiser !!!) I have exerimented with mixing the mash-out and sparge steps by using sparge water that is hotter than 75°C. All went well until I crossed the 80°C level after which I just got dreadful amounts of haze in my beer, even after cold filtering ! Funny really, because the thermometer never showed anything above 77°C. Ho hum, so I recommend you don't push that sparge temperature too high, I keep to 75-76°C these days, often ignoring the mash-out but I start the mash reasonably high anyway and so don't have a problem with the enzymes being active for that much longer.

At mash-end, open the tap carefully and run off the wort into a see through vessel, say a pint glass. Don't splash it, just trickle it into the glass. Check the wort clarity and run off until such time as the wort is free from bits of grain and is also free from haze. It should look as crystal clear at this point as the beer would eventually look in your glass . . . really ! If its got bits of solids in it then gently put these back into the mash tun and keep recirculating until it runs free. If its hazy you have likely not completed the "starch to sugar" conversion process and only more time will help. Of course, if your mash temperature has fallen too low you may also see this happening as the enyzmes have slowed down, in which case charge it with some boiling water and mix quickly in, stabilising the mash temperature back in the correct range for enzyme activity (say 63-65°C).

If you have mashed in correctly then you shouldn't have to run off too much from the mash tun. If I don't mash out (which involves disturbing the mash right near the end) then I do not have to do anything more than run off 100 ml for an SG sample and then its clear and can be run straight to the boiler.

One very important aspect of recirculating the wort in the mash tun is to avoid getting oxygen (air) dissolved into it. This happens when the wort is hot and the resulting chemical reaction, called oxidation, produces off-flavours in your finished beer. So please recirculate carefully !

During the sparge, keep the liquor level in the mash tun topped up to an inch or two above the grain bed. Some people run it dry before carrying on with the sparge but I prefer keeping the grain bed covered, less risk of it cooling down or getting disturbed.

Monitor the SG of the runnings and do not allow it to go below about 1010. Some people say 1008, others 1015. Whichever, the lower you go the more the runnings taste like cold tea and hence the more tannins etc you are rinsing out of the grain. Don't believe me about the tea ?! Try it !

Aim to collect the correct amount of liquor in your boiler, as determined in the tables above. Now, here's the catch ! You will likely find that the runnings are down to an SG of 1010 but that you are still 8 litres short in your boiler. The answer is not to keep on sparging but rather to add some of the sparge liquor directly to the boiler. All of this needs to be factored into your original recipe calculations, the stuff you run off at the end is very low in fermentable material in any case. I often add this amount into the boiler before starting the sparge step so that it can be already heating up to the boil, it just saves time.

After the sparge is complete, run the mash tun dry and scoop the grain into a bin. Some feed it to their pigs. A lack of pigs at home sees me putting mine in the bin. Heck, the house has already been turned into a brewery, if I made it into a farm as well !!

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