Geared for Mashing

by Pat Casey

With mash brewing you can control the fermentable qualities of the wort, and hence the character of your beers. Briefly, malt starch is converted to fermentable sugars by two enzymes, alpha amylase and beta amylase. Because the two enzymes work differently, and at slightly different temperatures, by manipulating the temperature and time of the mash you can produce worts of different fermentable qualities.

You can start mash brewing quite cheaply if you are prepared to accept several compromises. How cheaply depends on what brewing and general kitchen equipment you already have, or can borrow.

Mash Steps

Regardless of the scale the basic steps in mash brewing are the same:

i) mash the milled grain by infusing it in hot water according to a particular schedule of time and temperature,
ii) collect the extract from the grain and clarify or lauter it,
iii) hot rinse or sparge the remaining sugars from the grains,
iv) boil the extract and add hops,
v) chill the extract

Conveniently, lautering and sparging are done together.

There are various methods and means of carrying out these steps. The method and means I'll follow here is a simple hot water infusion in a combination mash and lauter tun. Such a tun is cheap, simple and easy to make. So too is a crude sparging device.

Finding a Boiler

However the major hurdle is a suitably sized boiler - and this is where you need to compromise. A stock pot is fine, especially if it is stainless steel, but domestic stock pots typically don't come in the size we want. For example if you wanted to have 20 litres of wort in the fermenter you would need a stock pot of about 28 litres to allow for evaporation during the boil, hop and other wastage after the boil, contraction of the wort after it cools, and sufficient freeboard in the pot to boil the wort vigorously. This is strictly a commercial size,
and such stock pots start at about $220 for stainless and $150 for aluminium.

For this money it would be better to spend a little more and buy a brewer's kettle - later of course, we're trying to do this as cheaply as possible.

You will probably need to buy a stock pot, but first a word about materials. Stainless is preferable. Aluminium may be affected by the acidity of the wort; it may pit and it may give the beer unwelcome flavours. However, this is a longer term concern, and while boiling tomatoes in aluminium is advised against, the wort at ideally about pH 5.5 is nowhere near as acidic as tomatoes. If you have access to a big aluminium stock pot, use it by all means to start, but I would not buy anything in aluminium.

That said, there are cheap stainless stock pots available. The local K-Mart at Katoomba sells 15 litre Indian made "Pronto" brand stainless stock pots with a stainless lid for about $22, they also sell a different brand of about 19 litres with a glass lid for about $70. Check similar stores for their stock and prices. As well, K-Mart and the like have regular discount sales. Do the rounds, prowl the aisles, and swoop when opportune. Unfortunately, big second hand stock pots seem rare.

As you have guessed one of the compromises is to produce a smaller volume, the other is to do a split boil. If you already have a pot, even if it is only 5 or 6 litres, just buying one of the example 15 litre pots would give you enough capacity to produce 13 or 14 litres of wort. And you could probably get 10 litres from a 15 litre pot alone. Buy as much capacity as cheaply as possible and for what you feel comfortable spending, and remember that stock pots are useful brewing equipment for general boiling and heating duties. They are also handy kitchen items, hence their secondhand rarity.

Even if you have a 28 litre stock pot, is your stove hot enough to vigorously boil 25 litres of wort? The only indication I can give you is this: I have a 38 or so litre kettle which weighs about 8kg, add to this about another 27 or 28 litres of wort, after sparging it takes about 40 minutes to bring the wort to boiling from about 50 degrees on the wok burner which is rated at 16 megajoules.

Despite their disadvantages short batches are more likely to be within the capacity of your stove, as well the whole physical process is a lot more manageable which will make it easier, especially with crude equipment.

Mash and Lauter Tun

Now to the promised mash and lauter tun. With the simple infusion method you mix hot water and grain to the desired sachrification temperature and let is stand for 90 minutes. The tun needs to be insulated. Next you collect the extract from the grain, filter it back through the grain, and then sparge the grain and collect the spargings. To do this you need to take the liquid from under the grains while leaving them in place. So we need a vessel with a tap, and the grains suspended above the level of the tap.

Firstly the vessel. You need a plastic food bucket of 20 litres with a lid. Food grade plastic is high density polyethylene, HDPE, and its recyling number is 2. You can probably scrounge a used one from a local restaurant or your home brew shop. As well buy a plastic tap with a backing nut. Now there are several methods of suspending the grain above the tap. One is to buy for about $30 a Phils Phalse Bottom from a home brew shop. This is is a convex disc of perforated plastic - several sizes are available. It sits in the bottom of your bucket, and at the false bottom's high point is an elbow fitting. Fit the tap to the bucket so it is level with the elbow fitting and connect them with a short length of vinyl tube. The tube should fit securely over the elbow and inside the tap barrel. If the tube is loose in the tap barrel build it up with some teflon tape. It does not need to be too tight a fit, so long as husks etc can't get in.

This is what I use for a lauter tun - I mash with direct heat in a stock pot that used to be my kettle.

There are several other methods which I have not tried but are used often enough. One is to use a grain bag made from nylon curtain material. Either make or buy a bag to fit your bucket. Boil it before using. When you have finished mashing and are ready to lauter and sparge, lift the bag so that it is clear of the tap and then clip it to the rim of the bucket. Another method is to use two tapered buckets, drill holes in the bottom of one and then put it in the other to create a false bottom. A fourth method is to use a slotted copper pipe.

Choose a diameter that will sit inside the tap barrel. Bend the pipe into a question mark shape so one end will fit into the tap. Block the other end of the pipe and then cut slots on what will be the underside of the pipe. The pipe will need to sit a centimetre or so off the bottom of the bucket. The stainless steel braid found on some coupling hoses may also offer possibilities.

Whichever method you use insulate the tun with polystyrene. Get several polystyrene fruit boxes and cut them into strips with a hot knife so that you can tape the strips right around the tun. Also cut a disc to fit the lid.

To sparge the grains it is best to deliver the water as gently as possibly so that you do not disturb the grain bed - it's your filter. So get a small HDPE bucket, about a litre or so, drill small holes in its bottom. The idea is to suspend the bucket about 10 to 15 centimetres above the grain bed, ladle your sparge water into the little bucket and gently swing it around inside the mash tun. How you suspend the bucket will depend on most likely the layout of your kitchen. I sit a pole between the tops of opposite cupboards and suspend the
bucket from that.

All you need now are a brewer's thermometer, a plastic kitchen jug or two, a long handled spoon and other miscellania.

Getting started with Mashing

This section is not to tell you how to mash brew, but how to get started with this equipment. Before you start mash brewing read as much as you can. As well you must master two techniques, sanitation and fermentation. An all grain wort requires extra handling and is more exposed to possible contamination than an extract wort, especially when it is cooling after the boil. Your sanitation must be scrupulous. Sodium metabisulphate is not up to the task as it inhibits rather than kills bacteria. Instead use Iodophor which is a no-rinse sterilant. And if your fermentation technique is poor there is not much point going to all the hard work of mashing. You must pitch lots of good yeast into a well aerated wort at the correct temperature and maintain the fermenting beer at a constant temperature.

That said, to business. Let's say you will be using two stockpots, one 8 and the other 15 litres. Use 3.5 kg of grain, aiming to end up with about 12 to 14 litres of wort in the fermenter with a gravity of about 1045. For your mash liquor you will need about 3 litres per kilo of grain, so about 11 litres and for your sparge water you will need about 15 litres to be safe, plus another 10 or so for extra infusions and contingencies, so roughly 35 litres in all. You need to boil all of your brewing water for about 10 minutes to drive off the chlorine, it can interact with phenols in the malt to produce chlorophenols - yuk. So boil about half the day before, and once it has cooled put it in one or more clean containers.

Let's also say that we will aim for a sachrification temperature of 66 degrees, the temperature of the mash liquor will need to be about 5 to 7 degrees above this depending on the volume. So when you are ready to brew boil up about 8 litres of water, add 3 litres of the previously boiled water and adjust with either more cold or boiling water to get a temperature of say 72 degrees. In the mash tun mix by parts the crushed grain and mash liquor, keeping a close eye on the temperature. Adjust the temperature with either hot or cold water. It is much better to mash in slightly cooler and add more boiling water rather than mashing in too hot because the excess heat may kill off the enzymes.

When you have mixed in all the grain with the right amount of water, stir thoroughly and check the temperature again. Adjust if necessary. If everything is OK put the lid on the tun and leave it. If you have an old sleeping bag wrap that around the tun to help insulate it. After 45 minutes stir the mash and check the temperature, you will probably need to add some more boiling water to bring the temperature back up. Malt starch gelatinises at 65 degrees, too much time spent below 65 degrees will give a poor mash. Sachrification should be complete after 90 minutes. You can check this with an iodine test.

During this last 45 minutes you will need to prepare your sparge water. Boil another 10 litres of water and add to it about 5 litres of pre-boiled cold water to get a temperature of about 75 degrees. You will also need to have a seperate 4 litres of boiling water to mash out. As well set up your little sparging bucket.

When sachrification is finished add the 4 litres of boiling water and stir to mash out, ideally bringing the temperature to 75 degrees. This stops further enzymatic activity, and raising the temperature will make the sugars less viscous and therefore easier to run off. If you are a few degrees short don't worry, you'll at least slow the enzymes down. After stirring cover the tun again and let it sit for another 10 or 15 minutes to allow the grain bed to settle.

Put the mash tun on a couple of plastic crates so that you can easily ladle the sparge water out of the pot on the stove to the sparge bucket above the tun, and so that you can conveniently place your collecting vessel. When stirring the mash try not to splash or suck air into it, strong and gentle is the way.

Sparging

Now you are ready to sparge. Partially open the tap and allow the liquid to run off into a jug. Gently pour the liquid back on to the top of the mash. Repeat this several times until you are not getting any coarse material in the run off.

Run the liquid off slowly and gently. If you run it off too quickly or suddenly, suction can cause the grain bed to compact and so reduce the flow. Even if the run-off is not too clear, do not recirculate too much, up to about 3/4 of the volume is OK.

To prevent splashing as you collect the wort and spargings, take a short length of plastic tube - from a bottling device is ideal - fit it inside the tap and then fit inside this tube a length of either 5 or 7 mm vinyl tubing that will reach to the bottom of your collecting vessel, a fermenter is fine. Try to avoid splashing or aerating hot wort as it can oxidise easily and cause staling in your finished beer.

Run the extract off, and once the liquid level is about 2 cm about the grain bed start to sparge. Try to match the sparging and run-off rates, and keep the grain bed covered. When you are getting close to your estimated pre-boil volume, taste some of the runnings from the mash tun. If they are still sweet, continue to sparge until you get your desired volume. If the runnings are dry tasting stop or wind up sparging. You can also take a hydrometer reading, cool the sample to room temperature and if the gravity is below 1012 stop sparging. Resist the temptation to squeeze that last bit of goodness out of the grain, you also squeeze out lots of badness.

Boiling your Wort

Gently stir the collected wort and take a sample to measure its gravity. Gently siphon the wort to your one or more stock pots. As you heat the wort stir it gently to avoid scorching it. Bring the wort to as vigorous a boil as possible given the freeboard you have. The mechanical action of a vigorous boil is important for the formation of hot break. Ideally you should boil all of the wort for 90 minutes, the first thirty without hops. This may not be possible because evaporation losses may be too great. Of course you can later dilute the wort to bring it back to the right gravity, but if your wort becomes too concentrated there can be problems. Partially covering the wort will reduce evaporation losses but depending on the freeboard it does increase the risk of a boil-over. And a boiling wort froths up when you add hop pellets. Instead you can boil the wort for 60 minutes, the first 15 or 20 without hops.

During the boil add the hops as per your recipe, although you may need to adjust the hop schedule it you boil for 60 minutes only. All of the wort needs to be hopped, but as you are using a split boil put proportionately more hops in the larger boiler. or adjust if your are boiling for a shorter time. Add kettle finings, if you are using them, about 15 or 20 minutes from the end of the boil.

When the boil has finished put the lids on and place the pots in a cold water bath as quickly as possible. Once they are in the water quickly stir each of them with a sterile spoon, stir strongly and gently trying not to aerate the wort. The aim here is create a whirlpool so that the spent hops and hot break settles into a mound on the bottom of the pot. During the boil various protein debris from mashing coagulates into flakes, this is hot break. The mechanical action of a vigorous boil helps greatly. Hot break may appear like soap flakes in the boiling wort, greenish if hops have been added.

Cooling your Wort

Cold break comes out as you either cool the wort, or chill the finished beer - causing chill haze. The quicker you can chill the wort the more cold break settles out. Cooling a given volume in two vessels will be quicker than in one. Stir the water but not so as to disturb the stock pots. When the water becomes warm, change it. If you can siphon this warm water into a container it is useful for the washing up that will shortly come. Tipping ice into the water bath to start is not effective, do it at the very end.

From now on your sanitation must be scrupulous, bacteria love warm wort. Spray Iodophor around the sink or bath, also spray around the edge of the pot lids. If you have a stock pot with a clear lid you will be able to see the cold break form and hopefully settle. If you have a very dense wort the break material and hop debris will take too long a time to settle. Once the wort has cooled and the break material settled, either pour the wort carefully off the spent hops and break material into your fermenter of hygienically siphon it. The unfortunate fact is that you will have between one and two litres of wastage in each stock pot.

At this stage you want to aerate the wort as much as possible, oxygen is essential for the first phase of yeast growth. Pouring the wort and allowing it to splash down the sides of the fermenter will help aerate it. If you use a siphon you can make a venturi aerator. Cut a 4 or 5 cm length of bottler tube and halfway along drill two small holes opposite each other, fit this to your siphon hose and another 15 cm length of hose. As the wort flows past the holes it will suck air into the wort, also allow the wort to splash as it exits the tailpiece. You can either pour or siphon the wort to another fermenter to aerate it more.

In all these steps your sanitation must be scrupulous. Take a sample of your chilled wort and measure its gravity, adjust with cold pre-boiled water if necessary. And finally, pitch lots of yeast.

I hope that gives you a good start for your first mash brew. As you can see you will need to make compromises, and which ones is something you will only find by
brewing. So for your first mash keep things simple, prepare thoroughly and set an entire day aside to do it. If you are a little out here or there, don't worry. If you need to make corrections or adjustments do them conservatively, an over hasty correction often makes things worse.

The small volume will be disappointing, but bear with it, and try to develop your technique. You will then see better what kind of improvements to equipment will best suit you and your circumstances. Read lots and use the digest to ask questions.

Good Brewing,
Pat Casey.