Partial Mash

Beer in its purest form is the fermentation of sugars extracted from barley. In fact the word beer is thought to originate from 'baerlic', the Old English word for barley. The barley is allowed to germinate and then the germination is halted and the barley is kilned. The result - malted barley - is chock full of the sugary goodness that nature intended to use to power the growth of the barley. This extraction of the malt is one of the dark arts of brewing, the process further muddied by the use of words such as mashing & sparging to describe what are in reality quite simple processes.

I've always shied away from using real grains in my brewing, prefering to use kits with pre-extracted & flavoured malt in a can or mucking around with various fruits & vegetables. It's a lot easier to attempt to make potato & carrot beer or dandelion beer as you don't really know what it will taste like at the end. That means it's hard to fail - you produce a gallon or so of a dry drink tasting vaguely of whatever you boiled up in the brewpot. You may not like the taste - and most of my friends generally didn't! -but that's a matter of taste.

Recently I've been tempted down the grain route. It's hard to produce a reasonable size brew entirely from grain as it needs a fair bit of liquid which means you have to have space, large pots & pans and a sturdy cooker. There is an alternative though - you can make half of the 'wort' (the unfermented beer solution) from grain and add in liquid malt extract for the rest. This gives you a lot more control over the flavours that come through in the beer than using a standard kit, but also means that you can brew a batch in an apartment. This is called a 'partial mash' or a 'mini-mash'.

I'm trying a partial mash version of a recipe for Pendle Witches Brew, a favourite drink of mine from back in the UK. The first thing to do is get your ingredients together - the recipe uses 2 kg of 'traditional' malted barley and 250g of crystal malt to provide the grain sugars

These grains are 'mashed' - ie soaked in water kept at around 66 degrees Centigrade for 90 minutes to allow the sugars to seep out. To make this process easier I'm using a grain bag (essentially a large tea bag) inside a large Esky
The water temperature is fairly critical. The grains will cool the water down when it is added so you need to heat the water up to a few more degrees than the intended mashing temperature. A rule of thumb is 6 degrees higher than mashing temperature
However as I'm adding the water to the mashing container instead of heating it up 'in situ' I lost a bit more temperature heating up the inside of the Esky and only got 65 degrees. Never mind - lesson learnt, I'll know to use an initial temperature of 74 degrees next time.
After you add the water give the bag some vigouros poking to make sure there are no dry clumps of grain inside the bag. Also be careful not to let the bag fall into the water, else you get the grains escaping like in the picture above.

Now comes the hard part - leave it for 90 mins and resist the urge to look at it, because every time you lift that lid you lose temperature. I'd love to say that I spent the time doing manly things like drinking beer & watching sports but I ended up tidying the flat, doing the hoovering & watering the plants.

After an hour & a half you can take a look at your mash. The temperature in mine had dropped to 62 degrees (I think I peeked too many times) but although this isn't great I think it just means I don't extract the optimal amount of sugars from the barley. However, even after the mash is completed there are still more sugars to be retreived. So first off pull the grain bag out and let it drain as much as possible

(Mmmmm - beer)

Next move the bag over to a large pot containing water at around 80 degrees that you prepared earlier

Soak the bag of grain for 10-15 minutes and you'll pull out a lot more of the remaining sugars, like a Yorkshireman reusing a teabag. This secondary extraction step is called sparging - it's normally done by trickling hot water over the grains but this way is a lot easier.
Make sure you drain the bag thoroughly at the end of the sparge - a handy spoon can help if you're tired of holding bags of grain above hot pans of water
Tip the wort from the Esky into the pot. The Original Gravity of my wort (a measure of the sugar content and hence the eventual alcohol content) was around 1030 at this point.
Next comes the boil. At this point you add any extras specified in the recipe - I added some canned malt (to bring the OG up a bit) and also some 'torrified wheat'. Turns out this was a breakfast cereal, which felt a bit wierd
and made it look like a porridge
Once the mixture comes to the boil (which takes a surprisingly long time on a cheap stove) add in any hops (I'm using Fuggles hops in the recipe) and vigorously boil it for 90 minutes. You may also need to add extras into the brew at nominated times - my recipe had me adding white sugar halfway through the boil, which is unusual as sugar is generally considered 'cheating' in home brew. I think it's a way of bringing up the strength of the beer whilst keeping a lighter taste.
You also need to add some more hops 15 minutes from the end of the boil - these are more for the smell of the beer than the taste. Speaking of which, your flat will now smell of a lovely mix of malty sugars with a hoppy nose. It's good to live somewhere warm so you can leave the doors open, and a patient partner is also a must. Thanks Liz.
Once the boil is over it's homebrew business as normal. Cool the wort down

then load it into the fermentor, The whole process of partial mashing took about 5 hrs in all, although a lot of it was waiting for things to steep or boil and you can get on with other things. It gave me around 10l of wonderfully smelling wort with a gravity of around 1100 - this is huge, stronger than the OG of a lot of wines. I added another 10l or so of water to bring the OG down to 1040 (which will give a roughly 5% alcohol beer - weaker than the recipe indicates, which is probably because I didn't pull all the sugars out of the barley), and once everything cooled down I chucked in (or 'pitched') the yeast. I'm using dried yeast but I've rejuvinated it in warm sugary water so it should be good & hungry & happy to be introduced to the wort.
Now it's just a question of waiting, and hoping that the end brew is worth the work!