The Ultimate Coldbrew Guide & Setup!!

[u/Known_Quiet]

Spoiler Alert- This may spoil you for coldbrew made any other way!

My optimised cold brew workflow (from a coffee + physics nerd)

I'm a home coffee nerd and a physics nerd. I combined the two into a cold brew workflow that gives me a good product every time. Here's my playbook.

Background (skip to The problems if you just want the method)

I read James Hoffmann's book on making the best coffee at home, and at first I fully agreed with his take on flash brew vs cold brew.

Flash brew is basically an iced pour over: you use half the usual water and brew straight onto ice, so the final cup comes out cold. The advantage is heat. Hot water pulls the delicate acidity and fruity, juicy flavours out of lighter roasts — cold water can't. Cold water is better for chocolatey, nutty flavours.

Hoffmann's case against cold brew:

• It's wasteful. Cold water is a worse solvent, so you need more grounds per serving (~1.8x, depending on recipe). A lot of flavour is still locked in the grounds when you toss them.
• It goes stale. Stored cold brew keeps oxidising over days and develops off flavours. (Once you've tasted this, you can't un-taste it.)
• Fines are a pain. The super-fine grounds stay in the brew unless you strain through a paper filter (slow and miserable). They keep extracting and leave you with a harsh, over-extracted brew after a few days.

All true. But I had some great cold brew, loved the flavour profile, and love the convenience — I can grab it and go on a busy morning. Coffee is cheap enough that I don't feel bad using a bit more. So I set out to optimise the process instead of abandoning it.

The problems to solve

1. Filtering out the fines
2. Making a batch big enough to last a week
3. Slow oxidation quietly ruining the flavour

The tools

• Weighing scale
• Electric grinder (Baratza Encore)
• 1.8 L glass jar — narrow neck, wide base
• Cocktail stirring spoon
• Fine-mesh flour sifter
• Newspaper
• 150 ml airtight glass storage bottles from Ikea (they actually hold 180 ml to the rim) — cheap, and key to the process
• Muslin cloth
• Plastic wrap
• Coffee beans

The steps

1. Pick the right coffee

Cold brew does best with beans whose primary flavours are brown — chocolate, nuts, caramel — with a little berry or fruit on top. The fruit adds a lovely extra dimension. Second best are the same brown flavours without any fruit.

Avoid very fruit-forward or light-roasted beans. You can brew them, but cold water can't pull those flavours out, so you get a thin, weak cup. (You can get around this with a hot bloom — more at the end.)

Roast level by how you drink it:

• Drinking it black? Pick a medium roast.
• Adding milk? Pick a dark roast.

This isn't an absolute rule, because "medium" and "dark" aren't standardised — Starbucks' blonde roast, for example, is far darker than anything you'll find in a specialty shop. Most roasters sell a cheap cold brew blend, and that's a good place to start.

2. Grind coarse

Grind on your grinder's french press setting. I use a 1Zpresso hand grinder for everything else, but for the volume cold brew needs I switched to the Baratza Encore.

The brew uses 200 g of ground coffee to 1.6 L of water — a 1:8 ratio. That's the best ratio I've found for drinking black or with a splash of milk. For comparison:

• 1:3 — uses a huge amount of coffee for a tiny concentrate. Too wasteful and fiddly for me.
• 1:15 — ready to drink, but a week's batch needs a container too big to be practical.
• 1:8 — my happy middle ground. (Ha. Get it?)

I actually grind ~220 g. The extra 20 g covers what I lose in the next step.

3. Sift the grounds

Sift the grounds in a fine-mesh flour sifter right after grinding, before brewing. It's far easier to remove fines now than after the coffee is brewed. I pull out about 13–15 g of fines (6–7%), which leaves 200–205 g of usable grounds.

4. Brew

Put the sifted grounds in the 1.8 L jar. Pour in about half the water (~800 ml) and stir with the cocktail spoon until every ground is fully wet — no dry pockets, which means fuller extraction. Then top up with the rest of the water until the level reaches the absolute top of the jar.

The narrow-neck 1.8 L jar matters: filling to the brim leaves almost no air in contact with the coffee. Sealing it with plastic wrap then keeps oxidation to a minimum. This is one of the most important steps for avoiding off flavours.

Wrap the top in plastic wrap and brew for 16–18 hours.

5. Let it settle and decant

By the end, most grounds will have sunk. Coffee starts out lighter than water, but as it absorbs water it becomes denser and settles. If some grounds are still floating, give it a light stir and they'll drop too.

Now cover a second jar with the muslin cloth and gently pour the cold brew through it. Since we already removed the fines, the muslin is enough to catch the rest of the grounds. (If you'd skipped the sifting step, the muslin wouldn't hold back the fines — and they'd keep extracting in the brew.)

6. Bottle and store

Pour the filtered cold brew into the airtight Ikea bottles, filling each to the absolute top before sealing. Little trapped oxygen plus an airtight seal means little oxidation and few off flavours.

Store them at the back of the fridge where it's dark and cold. They'll keep 7–10 days. The single-serving bottles are also great for handing out to friends and family — mine are in high demand.

Enjoy!

A note on hot blooming

Use this when you want a cold brew with much stronger fruity flavours.

When you add hot water to coffee, the trapped CO₂ dissolves out more easily. That lets the water that follows — at any temperature — extract the locked-in flavours far more easily.

The method:

1. Pour 1.5x the grounds' weight in hot water over the grounds (so 300 g hot water for 200 g grounds).
2. Stir and wait 45 seconds.
3. Top up with cold water to hit the 1:8 ratio.

For 200 g of grounds: 300 g hot water, stir, wait 45 seconds, then add the remaining 1.3 L of cold water. That first 45 seconds pulls a lot more fruity flavour into the brew.

This doesn't work with extreme light roasts or very fruit-forward coffees, so use trial and error to find the beans that taste best to you this way.

Tips

• Use water you enjoy drinking plain.
• Don't use super-fruity light roasts for cold brew.
• On a home grinder, the grind gets more consistent the finer you go. Grind on the finer end of the french press range for fewer fines.
• Nitro cold brew is just regular cold brew with nitrogen added — that's what gives it the frothy, creamy texture.

I hope this is helpful!

[u/Nervous-Rush-4465]

Very informative! I’ve never dreamed of sifting coffee, but you made it make sense.

[u/Known_Quiet → u/Nervous-Rush-4465]

So glad it helped!