Yarrow was used as the bitter flavoring in ale for many years before the use (and growth) of hops became widespread. Here in Ontario, Canada, much of the soil is not suitable for growing hops, but yarrow is very common -- and hardy. It has sprung up on many a boulevard strip in my town as people have stopped mowing their lawns and the boulevards (owned by the city, but expected to be kept up by homeowners). I use yarrow alone and in combination with other herbs for teas, so I thought I'd try making ale with it.

I found a recipe online that makes 5 imperial gallons (160 oz gallons) and adapted it to make one imperial gallon. I don't like using liquid malt extract (LME), so I used dried malt extract (DME) instead. It's also much easier to store remainder amounts of DME. And since I was fermenting in a glass jug, I drained the wort off the boiled and steeped yarrow, rather than fermenting with yarrow in it.

I also go into much more detail about individual steps.

Beers made with bitter flavorings other than hops were called gruit. It was not until the 16th century that hops became the bittering standard for beer. Google either "yarrow ale history" or "gruit" for more history.

Step 1: Equipment

If you start your brewing adventures on a small scale (one gallon at a time), most of your equipment will be items from a well-stocked kitchen (or if you have to buy, the items will be useful for many other culinary adventures).

Things you may have to buy:

a 160 fl oz jug or 4 quart (128 fl oz) jug. If you can't recycle one from a cider or juice vendor, brew stores often sell them. I've picked up one or two in yard sales.
a fermentation lock (from a brew or wine store, or on-line)

If you have a 1 1/2 - 2 gallon capacity food-grade plastic bucket with a tight fitting lid, you could drill a hole in the lid to fit the fermentation lock.

The jug and fermentation lock can also be used for making wine.

A note on the fermentation lock: be sure the pipe opening extends below the bottom of the plug. If it doesn't, the lock can harbor the bacteria you're trying to keep out on the pipe bottom.

Another item you may have to invest in is a digital scale that has multiple units (oz/lb, kg, and g) and has a taring function (see Step 4 for an explanation of taring and how to do it). Many European and British recipes use weight measurements rather than the volume measurements common in North American recipes. Weight measurements are more precise than volume, because different lots of an ingredient can have different weights for the same volume due to factors such as humidity or if air has settled out of it during storage. Weight measurements are also common for soap, toiletry, and wine recipes. The cost for one can vary from $15 to $50, depending on vendor, functionality or if it is on sale.

Items commonly found in kitchens:

2 liter/quart measuring cup: makes measuring out 4 liters (each ~ 35 fl oz) or 4 quarts (each 32 fl oz) of water easy. Outfitted with a lid (or a plate as a lid), it can be used to steep the yarrow.
8 quart stainless steel stock pot with lid: for holding the wort (can substitute a 6 quart stainless steel pot with lid)`
1 quart stainless steel bowls: to hold measured ingredients while weighing and before adding to the wort
Corning ware soup bowls and plates: to hold measured ingredients while weighing and before adding to the wort
stainless steel or plastic spoon: must be able to tolerate boiling temperatures
stainless steel whisk: for breaking up dried malt extract lumps that may form when adding it to hot liquid
strainer: to separate the yarrow from the wort
1 liter measuring cup: to use for moving the wort to the fermentation jug or beer to bottles (optional)
funnel: to direct fluid into jug and beer bottles
basin: for setting up a cold water bath to cool the wort
siphon tubing: to move beer from the fermentation jug to bottles (if you use this, you won't need the funnel for beer bottling)
spray bottle: to hold the sanitizer fluid to easily sanitize small items
half cup measure or ladle: to put a sufficient amount of sanitizer fluid into larger items

Step 2: Cleaning

Everything you use in brewing should be cleaned and sanitized.

Cleaning gets rid of the gross dirt; sanitizing does away with the microscopic organisms (such as vinegar bacteria) that could compromise or destroy your brew.

Detergent suffices for most cleaning. Commercial establishments use lye to really get their tanks clean.

If you've left bottles around uncapped and with old yeast in them, you may have some stubborn grime to deal with. Soaking will soften and loosen things up. I haven't found a bottle brush that easily gets into curves and bottoms of jugs and bottles. Lee Valley sells a bottle washing kit that scours without a brush. I've improvised a similar system with BBs. Pour some in a bottle or jug with a half cup or less of lightly soapy water. Swirl, swirl, swirl in every direction. Run the BBs over any grungy spots until they are gone. Pour the soapy water and BBs out into a strainer. Rinse with clear water and your cleaning is done! I empty the pellets onto a folded paper towel on a saucer to dry out the BBs before storing them for reuse.

Step 3: Sanitizing

I bought Oxy-San when I ordered by dried malt extract and ale yeast. I've used a metabisulphite for years in wine making, but I assiduously rinse the bottles and jugs afterwards to get rid of all trace of sulphite since I'm sensitive to it. The Oxy-San is a no-rinse sanitizer; the pellets produce a hydrogen peroxide solution when dissolved in hot water. The hydrogen peroxide breaks down into water, so that is why it does not need to be rinsed (and rinsing can re-introduce some of the contaminants you were getting rid of).

Fifteen grams of the pellets (~1 tablespoon) makes up 1 gallon of sanitizing solution when added to hot water. A 250 gram packet of the stuff makes up 16 gallons of solution; I paid $7 for it. I find that a half-gallon of sanitizing solution is enough to handle a brewing or bottling session. I put some in a spray bottle for sanitizing small objects such as stirring spoons, small bowls and saucers, funnels and so forth. I use a half cup measure as a handy ladle to put the sanitizer into larger bowls, jugs, or bottles. You don't have to fill such vessels, simply put in enough to easily swirl over all interior surfaces and then empty out into a sink. The release of oxygen from the solution kills bacteria and mold spores, but its efficacy diminishes as the breakdown continues, so I don't attempt to reuse it.

Step 4: Taring a Digital Scale

If you already know what taring is and how to do it, go on to the next step.

1. When you turn on a digital scale, it will register zero. All the weights in this Instructable are grams, so hit the unit button until "g" shows up in the display if it doesn't already.

2. When you put a bowl on the scale, it will display the weight of the bowl. How do you use a bowl to hold an ingredient and only have the ingredient's weight show on the scale? By taring.

3. With the bowl on the scale, turn it off and turn it on again. The scale displays zero! The scale's taring function has kicked in.

4. Now you can add the ingredient to the bowl until the desired weight is reached.

5. When you take the bowl off the scale to empty the ingredient, you'll see the weight of the bowl as a minus figure. If you put the same bowl (now empty) back on the scale, it will display zero. The taring weight is remembered until the scale turns off (on its own after a small amount of time) or you turn it off. If you have two bowls the same size and weight, you don't need to do a new taring to use the second bowl.

Step 5: Ingredients

For 160 fl oz (Canadian gallon) you will need:

5 liters minus 1/2 cup of spring water or filtered water (I filter my own with a Brita system)
306 g dried malt extract
90 g honey
30-60 g yarrow (leaves from young plants (before flowering) can be used as well as flowers) The colour of the flowers doesn't matter: all of the pictured colours grow in my yard and have the same pungency. On your first run with this, harvest the larger amount, but do the initial steep with the smaller amount. If the pungency seems weak to you, add more yarrow when you add the steeped yarrow to the wort.
1/2 teaspoon of ale yeast

For 128 fl oz (US gallon) you will need:

4 quarts spring water or filtered water
230 g dried malt extract
67.5 g honey
22-45 g yarrow
1/2 teaspoon of ale yeast

You may be lucky enough to have a brewer supply shop near you. I ended up ordering the dried malt extract and ale yeast from Beer Grains in Pembroke, Ontario -- extensive diversity of supplies and tools for the home brewer which is close enough to me that my order arrives in two days. Yeast packets are commonly sized to be sufficient for a 25 liters batch of brew; a half teaspoon is enough for a gallon batch.

Step 6: Make the Wort

Measure out the amount of spring or filtered water you are using. If chlorinated tap water is all you have available you will have to boil it for 10 minutes to drive off the chlorine, which hampers yeast growth and flavor.
While the water is coming to a boil (and during the 10 minute boil to drive off chlorine), pick (I have yarrow growing on the boulevard in front of my house on a low-travel street) and weigh your yarrow. In mid-summer the flowers give the most flavor. Earlier in the year before the flowers form and bloom, the leaves are as pungent as the flowers and can be used. The pungency is the flavoring agent. Put the yarrow in a 2 liter or higher capacity sanitized vessel you can pour boiling-hot water into (for the initial steep). Weigh out the dried malt extract into a sanitized bowl and the honey into another sanitized bowl.
Once the water has boiled, take it off the heat (turn off the burner) and pour about 2 liters of it over the yarrow. Cover and let steep.
Ladle some of the boiled water over the honey to make it more liquid (and easily get it all out of the bowl).
Slowly pour and stir in the dried malt extract (DME) to the remaining boiled water. You want it all dissolved; no lumps! You can use a sanitized whisk to get out any lumps if stirring won't do it. However, taking your time to add the DME to the water while maintaining a good stir will greatly lessen the size and frequency of lumps. It's starting to smell like beer here!
Pour in the liquidy honey and stir.
Pour in the steeped yarrow, flowers and all, and stir.
Ladle some the wort into one of your empty bowls and cover it with a sanitized plate. It has to cool before you can use it to activate the yeast.
Bring the completed wort to a boil and let gently boil (covered) for thirty minutes.

Step 7: Cool the Wort and Prep the Yeast

The wort has to cool to lukewarm before you can add the yeast and put it into your fermenting vessel (jug).

In the winter time, this is easy: stick it outside, even in a snow bank

In the summer time, the same effect can be achieved by sticking it in a basin or sink with ice water.

While the main wort is cooling, check if the wort you set aside in a bowl has cooled to lukewarm: sanitize your finger and stick it in the wort. If it's "ouchy", it has to cool more. Or use a sanitized food thermometer. A temperature between 80 and 90 deg F is suitable. Sprinkle 1/2 tsp of the ale yeast on cooled wort and cover again.

Step 8: Start Fermentation

Once the wort has cooled to lukewarm ( 80 to 90 deg F), strain out the yarrow and add the yeast, which should be bubbly by now. With the equipment I have, I strain out two liters at a time and add the yeast to the first lot. This goes into the sanitized jug and I top it up with another strained 2 liter lot, and and then the last strained liter.

Fill the fermentation jug to just below where it narrows for the neck. If wort is up on the neck, it can overflow the fermentation lock once fermentation begins in earnest.

Set up your fermentation lock with sanitizer solution. Locks have different constructions, but all involve having the CO2 produced by fermentation pass through water and escape. The water keeps bacteria and mold spores from drifting into the fermentation vessel.

Set the jug in a cool ( 65 - 75 deg F), dark place for 6 to 7 days. I use my basement, which goes to the upper part of the temperature range in the summer, so 6 days suffices for the initial fermentation. In the winter, I need to let it go longer. Caution:Temperatures higher than 75 deg F encourage the breakdown of alcohol into compounds that impart a "lighter fluid" taste to your brew.

Step 9: Bottling Day

This can be after 6 days (in summer) or 7 days (in winter) of fermentation. As your brewing adventures progress, you may decide invest in a hydrometer and use it to precisely ascertain how much alcohol is in your beer or ale and how much sugar is still available for in-bottle fermentation.

In-bottle fermentation is an easy way to carbonate homebrew, but you must use bottles than can withstand the pressure that builds up:

sturdy glass with tight sealing caps (your standard beer bottles)
sturdy glass bottles with swing caps
plastic bottles with tight fitting screw on caps (your standard soda bottles)
plastic bottles designed to house home brew (shown here)

All of these can be re-used, provided they are clean and sanitized.

How many bottles will you need? Number of bottles = Jug size in fluid ounces / bottle size in fluid ounces. Oh dear, you do the calculation using 12 oz bottles and find you will have 4 (160 oz jug) or 8 (128 oz jug) ounces left over. Set that bit aside in a jar. let it clear, and enjoy a preliminary still beer while waiting for your bottles to fizz.

Here's what to gather together on bottling day:

jug of fermented beer (it should no longer be in active ferment)
bottles with matching caps (clean! see Step 2 for a handy way to get grunge out of bottles)
at least a quart of sanitizer -- maybe more if you are using smaller bottles
spray bottle for some of the sanitizer (optional -- I put caps in a small bowl and poured sanitizer over them)
1/8 teaspoon measure to measure out priming sugar
half cup measure to use as a ladle (or use a ladle if you have one)
small bowl with a tablespoon or so of sugar (white or organic) to feed in-bottle fermentation
1 meter (3 feet or so) length of siphon hose -- I use quarter-inch hose I got at a hardware store. Clear or translucent lets you see what is going on with the liquid.

Step 10: Prepping the Bottles

As mentioned in the previous step, the bottles you use must be clean (no grunge anywhere inside; its presence is a sure way to spoil the brew -- review Step 2 for cleaning tips). Once you start brewing regularly, develop the habit of at least rinsing out brew bottles within an hour of consumption. It will be harder to get out that bottom layer of spent yeast the next day; left longer they can attract insects.

Pour at least a quarter cup of sanitizer in each bottle. Thoroughly swirl it around the inside and pour out. Put your caps in a small bowl and cover with sanitizer (or spray the inside of screw caps with it).

Pour 1/8 of a teaspoon of sugar into each bottle. This feeds the yeast (though much has settled out, there is still some throughout the brew) and the gas produced carbonates the contents. Yes, a little more alcohol is produced, but not much.

Step 11: Siphon Beer Into the Bottles

Put your siphon hose into the remainder of your sanitizer, immersing one end so liquid enters the hose. Lift the hose so sanitizer travels the length of its inside. It and your hands are now sanitized.

How a siphon works:

the liquid source sits higher than the liquid recipient
with one end of the hose in the source, liquid is suctioned through the length of the hose and the other hose end is placed in the recipient container
air pressure on the surface of the source liquid keeps up flow to the recipient as long as the recipient hose end is lower than the source hose end.
you can stopper the recipient end of the hose with your finger to move it from one container to the other and as long as no air enters the source end of the hose, the flow will continue when you unstop the recipient end

The easiest way to suction liquid through the hose length is to suck on the recipient end of the hose. Do it quick and don't stick the recipient end to the bottom of the recipient bottle and sanitation is minimally compromised, if at all. I've used this method on countless jugs of brew and wine and never had a problem.

The source end of the hose should be just above the yeast layer in the jug bottom. Situate the bottles you are filling so that their mid-neck is lower than that point. Have a table and chair set? Jug on the table and bottles on the chair gives you the right height differential. I usually put the bottles in basin or pan in case of drips when moving the hose end from one bottle to another.

Holding the source end in a stable position in the jug, suction (suck) the brew through the hose and quickly stopper it with your finger. Bring it to your first bottle, lift your stoppering finger, and insert the hose end about an inch into the bottle.

Once liquid is within two inches of the bottle opening, lift the hose (still flowing), stopper it with your finger, and move it to the next bottle.

Monitor the location of the hose end in the source. You will have to tilt the jug to get the last of the clear brew into your last bottle.

Cap the bottles. Once the bottle sides dry you can apply paper labels (washable school glue makes removing them later easy). I like to identify the type of brew and the date of its bottling.

The ale should sit in a dark, cool place for 14-21 days so it can carbonate and clear (the longer it sits, the clearer it gets). Then enjoy!

Step 12: Clean Up!

Run some sanitizer through the siphon hose and hang it to dry.

If you want to reuse the yeast, add a half cup of spring water to the jug, swirl, and empty into a pint jar. Label so you know it is second generation ale yeast and store it in the refrigerator. You should have enough for 3 or 4 jugs. Use a 1/4 cup of this and prep it as outlined in Step 7, adding it to some cooled wort. If it doesn't get active, then discard and continue with dry yeast.

Thoroughly rinse the jug, getting out all traces of wort and spent yeast. Rinse with sanitizer. Renew the water in the fermentation lock and reinstall it. You can now store the jug away. Dust may accumulate on its outside, but the inside will stay clean.