Coffee Troubleshooting: Fix Bitter, Sour & Weak Coffee

Your coffee tastes wrong. Maybe it's too bitter, too weak, or just... not good. You made it the same way as always, but something's off.

Before you blame yourself or your coffee maker, let's figure out what went wrong. Most coffee problems have simple fixes that take less than a minute.

Here's how to diagnose bad coffee and make it taste better—no fancy equipment or coffee science degree required.

Before You Troubleshoot Anything: Check Your Beans

The #1 reason coffee tastes bad? Stale beans.

Know when your coffee was roasted (not an expiration date). If your beans were roasted more than a month ago, that's probably your entire problem.

Quick freshness test:

Open the bag and smell the beans.

• Fresh beans smell intense - fruity, chocolatey, bold, aromatic
• Stale beans smell muted or like nothing - faint coffee smell or barely any smell at all

Stale coffee tastes flat, bitter, or like cardboard no matter how you brew it. No amount of troubleshooting fixes old beans.

If your beans are stale: Buy fresh beans with a roast date within the last 2-4 weeks. Problem solved.

If your beans smell great and are recently roasted: Keep reading—it's a brewing issue we can fix.

Quick Problem Finder

Find your problem below and jump to the solution:

Taste Problems (Any Brewing Method):

• Coffee tastes too bitter
• Coffee tastes sour or acidic
• Coffee tastes weak or watery
• Coffee tastes burnt
• Coffee has weird chemical/plastic taste
• Coffee tastes different every day

Drip Coffee Maker:

• Coffee maker stopped working or is really slow
• Coffee from drip machine tastes bad but used to be fine

French Press:

• Lots of grounds/sludge in coffee

Pour-Over:

• Coffee tastes muddy or gritty
• Takes forever to drain
• Results are inconsistent

Espresso Machine:

• Shots pull too fast (watery)
• Shots pull too slow (barely drips)
• No crema on espresso
• Espresso tastes sour
• Machine says "descale"
• Milk frother not working

Super-Automatic:

• Makes weak/watery coffee
• Coffee tastes burnt or bitter

Cold Brew & Iced Coffee:

• Cold brew tastes weak
• Cold brew tastes too bitter
• Iced coffee tastes weak or watery

Reusable Pods/Keurig:

• Reusable pod makes weak coffee
• Pod overflows or doesn't work
• Tastes like plastic

Grinder & Storage:

• Grinder clogs or makes uneven grounds
• Grinder makes burnt-tasting coffee
• Beans go stale really fast
• Coffee smells weird after brewing

Universal Taste Problems (Any Brewing Method)

These problems happen with any coffee maker. Fix these first before diving into equipment-specific issues.

Why Does My Coffee Taste Too Bitter?

What it's like: Harsh, burnt, overly strong, or leaves a dry, unpleasant taste in your mouth.

What's happening: You're pulling too much flavor out of the coffee. It's been in contact with water for too long or the water was too hot.

Simple fixes (try these in order):

Fix 1: Use less coffee

• Try 1 tablespoon of coffee per 6 ounces of water (instead of heaping tablespoons)
• If you're eyeballing it, use a bit less than usual

Fix 2: Brew for less time

• Drip machine: Can't change this, move to Fix 3
• French press: Press down at 3 minutes instead of 4
• Pour-over: Pour a bit faster

Fix 3: Let your water cool down

• If you're boiling water in a kettle, let it sit for 30-45 seconds before pouring
• Don't pour boiling water directly on coffee

Fix 4: Try filtered water

• Hard water (common in Prairie provinces) makes coffee taste more bitter
• Even a basic Brita filter helps

Still bitter? Your beans might be too dark of a roast for your taste. Try a medium roast next time.

Why Does My Coffee Taste Sour?

What it's like: Sharp, tangy, acidic, makes your mouth pucker.

What's happening: Not enough flavor is coming out of the coffee. Either you're not using enough coffee, the water isn't hot enough, or you're not brewing long enough.

Simple fixes (try these in order):

Fix 1: Use more coffee

• Try 2 tablespoons per 6 ounces of water (instead of 1)
• If you have a scale, use 1 part coffee to 15 parts water (example: 20g coffee to 300g water)

Fix 2: Make sure water is hot enough

• Water should be just under boiling (around 200°F, but you don't need a thermometer)
• If using a kettle: bring to a boil, let sit 30 seconds, then pour
• If your coffee maker doesn't seem to heat water enough: run it with just water first to warm it up, dump that water, then brew

Fix 3: Brew longer

• French press: Wait 4 minutes before pressing (instead of 3)
• Pour-over: Pour more slowly
• Drip machine: Can't change this

Fix 4: Check your beans again

• Weak coffee is often a stale bean problem
• Light roasts naturally taste more acidic—if you don't like that, try medium roast

Still weak or sour? Your coffee maker might not heat water hot enough. Consider a different brewing method or a better machine.

Why Does My Coffee Taste Weak or Watery?

What it's like: Thin, diluted, lacks body or flavor. Tastes like coffee-flavored water.

What's happening: Same as sour coffee—not enough extraction. Not using enough coffee, water too cool, or beans are stale.

See "Why Does My Coffee Taste Sour?" above for all the fixes—they're the same.

Why Does My Coffee Taste Burnt?

What's happening: Water is too hot, or using a blade grinder that's heating up the beans.

The fix:

• Don't use boiling water—let it cool 30-45 seconds after boiling
• If using a blade grinder: grind in short bursts (5 seconds on, 5 seconds off) to prevent overheating
• Better solution: upgrade to a burr grinder (doesn't heat beans)

Coffee Has Weird Off-Taste

What it's like: Tastes metallic, like chlorine, or has a chemical/plastic flavor.

Simple fixes:

If it tastes like chlorine or chemicals:

• Use filtered water (basic pitcher filter works)
• Don't use tap water straight from the faucet

If it tastes metallic:

• Your tap water probably has iron or copper in it
• Switch to filtered or bottled water

If it tastes like plastic or has a weird chemical taste:

• Clean your coffee maker thoroughly
• For new machines: run 2-3 cycles with just water (no coffee) to clear out manufacturing residue
• For old machines: might be time to replace it

Coffee Tastes Different Every Time

What's happening: You're probably not measuring consistently.

The fix:

• Use the same amount of coffee every time (measuring spoon or scale)
• Use the same amount of water
• Set a timer if you're brewing manually
• Use filtered water (tap water quality can fluctuate)

Pro tip: Eyeballing it never works. Spend $10 on a simple kitchen scale or use a tablespoon measure.

Drip Coffee Maker Problems ⤵️

Coffee Maker Not Brewing or Brewing Slowly

What's happening: Mineral buildup from hard water is clogging it.

The fix:

1. Mix equal parts white vinegar and water
2. Run a full brew cycle with this mixture (no coffee)
3. Run 2-3 cycles with plain water to rinse
4. Should work better now

Do this every 3 months if you have hard water, every 6 months if you have soft water.

Coffee From My Drip Machine Tastes Bad

What's happening: Old coffee oils are building up inside the machine.

The fix:

1. Wash the carafe and filter basket with soap and water
2. Run a vinegar cycle (see above)
3. Make sure you're cleaning it regularly

Worth knowing: Old coffee residue adds bitter, stale flavors. Clean your equipment every week.

French Press Problems ⤵️

French Press Has Lots of Grounds in the Coffee

What's happening: Your coffee is ground too fine for French press.

The fix:

• If buying pre-ground: ask for "coarse grind for French press"
• If grinding at home: grind it coarser (bigger chunks, like sea salt)
• Pour slowly and carefully—leave the last bit in the press

Pour-Over Problems ⤵️

Pour-Over Tastes Muddy, Gritty, or Has Sediment

What's happening: Grounds are too fine, or you're getting coffee particles through the filter.

The fix:

• Use a coarser grind (grounds should look like coarse sand, not powder)
• Rinse paper filter with hot water before brewing
• Pour gently—aggressive pouring can cause grounds to go through filter
• If using a metal filter: expect some sediment (that's normal)

Worth knowing: A little bit of fine sediment at the bottom is normal. A muddy, gritty texture means grind is too fine.

Pour-Over Takes Forever to Drain

What's happening: Coffee is ground too fine, clogging the filter.

The fix:

• Use a coarser grind
• Don't overfill the brewer—pour in stages instead of all at once
• Make sure filter is sitting properly in the cone

Pour-Over Is Inconsistent

What's happening: Not measuring, or pouring technique varies.

The fix:

• Use a scale to measure coffee and water (30g coffee to 500g water is a good starting point)
• Use a timer
• Pour the same way each time—slow, steady, spiral from center outward
• Use water that's the same temperature each time (just off boiling)

Worth knowing: Pour-over is the most technique-sensitive method. Being consistent is key.

Espresso Machine Problems ⤵️

Espresso Pulls Too Fast (Watery Shots)

What's happening: Water rushes through the coffee in under 20 seconds. Espresso tastes weak, sour, or watery.

The fix:

For machines with a grinder built-in:

• Adjust grinder to a finer setting (usually a dial or button)
• Make it one notch finer, test, adjust again if needed

For machines where you add your own ground coffee:

• Use finer ground coffee (if buying pre-ground, ask for "espresso grind - fine")
• Pack the coffee more firmly into the portafilter (if you have a manual machine)
• Use more coffee (try 18-20g for a double shot)

Target: Espresso should take 25-30 seconds to pull a double shot.

Espresso Pulls Too Slow (Or Barely Drips Out)

What's happening: Coffee is ground too fine or packed too tight. Takes over 40 seconds and tastes bitter.

The fix:

For machines with built-in grinder:

• Adjust grinder to a coarser setting
• Make it one notch coarser, test, adjust again if needed

For machines where you add ground coffee:

• Use coarser ground espresso (still espresso grind, just not powder-fine)
• Don't pack the coffee so hard into the portafilter
• Use slightly less coffee

Target: Should take 25-30 seconds for a double shot.

No Crema on Espresso

What's happening: Beans are too old, or machine isn't creating enough pressure.

The fix:

• Use beans roasted within the last 2-3 weeks (crema disappears after beans are 3-4 weeks past roast)
• Grind finer to slow down the shot
• Use more coffee
• Make sure machine is fully heated up

Worth knowing: Crema comes from fresh beans more than anything else. If beans are old, you won't get crema no matter what you do.

Espresso Tastes Sour Even With Fresh Beans

What's happening: Under-extraction—water is too cool or passing through too fast.

The fix:

1. Let machine heat up fully before pulling shots (at least 10-15 minutes)
2. Grind finer so water moves through slower
3. Use more coffee
4. Check that your machine is actually heating water hot enough (some cheap machines don't)

Machine Says "Descale" or Water Flow Is Weak

What's happening: Mineral buildup from hard water is clogging the internal parts.

The fix:

1. Buy descaling solution made for espresso machines (don't use vinegar—it can damage some machines)
2. Follow your machine's descaling instructions (usually in the manual or online)
3. Run the full descaling cycle
4. If you have hard water, do this every 2-3 months

Prevention: Use filtered water in your espresso machine. Hard water destroys these machines over time.

Worth knowing: This is the #1 reason espresso machines die early. If you have hard water (common in Prairie provinces), use filtered or bottled water.

Milk Frother Not Working or Making Watery Milk

What's happening: Steam wand is clogged, or you're using the wrong technique, or milk is too hot.

The fix:

If frother isn't steaming:

• Purge the steam wand first (run steam for 2-3 seconds before putting wand in milk)
• Check that steam wand tip isn't clogged—clean it with a pin if needed
• Make sure machine is fully heated up

If milk is watery/not foamy:

• Use cold milk straight from the fridge
• Keep the steam wand tip just under the surface of the milk
• Stop steaming when milk reaches about 140-150°F (too hot = can't foam)
• Use whole milk or 2% (skim milk is harder to foam)

After every use: Wipe down the steam wand and purge it (quick burst of steam) to prevent milk buildup.

Super-Automatic Machine Problems ⤵️

Super-Automatic Makes Weak or Watery Coffee

What's happening: Grinder setting is too coarse, or machine isn't using enough coffee.

The fix:

1. Adjust the grind setting to finer (check your manual—usually a dial inside the bean hopper)
2. Increase the coffee strength setting (most machines have this in the menu)
3. Decrease the water amount per shot (make a smaller, stronger shot)
4. Check that beans are fresh (stale beans won't produce good crema or strong flavor)

Super-Automatic Coffee Tastes Burnt or Bitter

What's happening: Grinder is set too fine, or using too much coffee, or beans are too dark.

The fix:

1. Adjust grind setting to coarser
2. Decrease coffee strength setting
3. Try a lighter or medium roast (dark roasts can taste burnt in super-automatics)
4. Clean the brew unit—old coffee oils add bitterness

Worth knowing: We don't roast our beans oily, which is important for super-automatics. Oily beans clog the grinder and cause problems.

Cold Brew and Iced Coffee Problems ⤵️

Cold Brew Tastes Weak or Watery

What's happening: Not enough coffee, or didn't steep long enough.

The fix:

• Use a 1:4 ratio (1 part coffee to 4 parts water) for concentrate, or 1:8 for ready-to-drink
• Example: 1 cup (80g) coffee to 4 cups (950ml) water
• Steep for 12-24 hours in the fridge (or room temperature for 12-16 hours)
• Use coarse ground coffee (like for French press)

Worth knowing: Cold brew should be strong—you can always dilute it with water or milk after.

Cold Brew Tastes Bitter or Too Strong

What's happening: Steeped too long, or used too much coffee.

The fix:

• Steep for less time (try 12 hours instead of 24)
• Use less coffee (try 1:5 or 1:6 ratio instead of 1:4)
• Dilute the finished cold brew with water, milk, or ice
• Use a coarser grind

Worth knowing: Cold brew concentrates are meant to be diluted. If drinking it straight and it's too strong, just add water or milk.

Iced Coffee Tastes Weak, Sour, or Watery

What's happening: Hot coffee diluted with ice = weak coffee.

The fix:

Method 1 (Best): Make coffee double-strength, then pour over ice

• Use 2x your normal amount of coffee
• Brew normally with hot water
• Pour immediately over a glass full of ice

Method 2: Make coffee normally, let it cool, then add ice

• Takes longer but doesn't require calculation
• Make regular-strength coffee
• Let cool to room temp or refrigerate
• Add ice when ready to drink

Method 3: Make coffee ice cubes

• Brew coffee, freeze it in ice cube trays
• Use coffee ice cubes in your iced coffee so it doesn't get watered down

Pro tip: Iced coffee needs to be brewed stronger because ice dilutes it. Don't just pour regular hot coffee over ice.

Reusable Pod and Keurig Problems ⤵️

Reusable Keurig Pod Tastes Weak or Bad

What's happening: Not enough coffee in the pod, or coffee is ground wrong.

The fix:

• Fill the pod completely (don't pack it down hard, just fill it full)
• Use medium-fine grind (finer than drip, coarser than espresso)
• Tamp it very lightly with your finger
• Use fresh beans—stale coffee tastes especially bad in pods
• Clean your Keurig regularly (old coffee oils add off-flavors)

Worth knowing: Reusable pods work best with fresh, good-quality coffee. Grocery store pre-ground often tastes weak or stale in reusable pods.

Reusable Pod Overflows or Doesn't Work

What's happening: Pod is overfilled, coffee is too fine, or machine needle is clogged.

The fix:

• Don't pack the coffee down hard—just fill loosely
• Use a slightly coarser grind
• Make sure the pod filter isn't clogged—clean it after each use
• Clean the Keurig needle (the part that punctures the pod) with a paperclip

If water barely comes out: Run a descaling cycle on your Keurig—it's probably clogged with mineral buildup.

Coffee From Pods Tastes Like Plastic

What's happening: Reusable pod needs cleaning, or machine needs cleaning.

The fix:

1. Wash reusable pod thoroughly with soap after each use
2. Run a brew cycle with just water (no pod) to clean the machine
3. Descale your Keurig if you haven't in a while
4. Try a different reusable pod brand—some are better quality than others

Grinder and Storage Problems ⤵️

Grinder Clogs or Produces Uneven Grounds

What's happening: Oily beans, old coffee buildup, or grinder needs cleaning.

The fix:

• Clean your grinder every 2-4 weeks
• For blade grinders: wipe out with dry cloth
• For burr grinders: remove burrs and brush out old coffee
• Don't use oily, super-dark roasted beans (they gum up grinders)
• Grind a small amount of rice to absorb oils and clean (then discard)

Worth knowing: We don't roast our beans oily, which is better for grinders. Oily beans from other roasters can clog and damage grinders over time.

Grinder Makes Coffee That Tastes Burnt

What's happening: Blade grinder is heating up the beans while chopping them.

The fix:

• Grind in short bursts (5 seconds on, 5 seconds off) to prevent overheating
• Don't grind for longer than 20-30 seconds total
• Better solution: upgrade to a burr grinder (they don't heat beans up)

Beans Go Stale Really Fast

What's happening: Improper storage is accelerating staleness.

The fix:

• Store in an airtight container (not the bag they came in, unless it has a good seal)
• Keep in a cool, dark place (not on the counter near the stove)
• Don't refrigerate or freeze (moisture gets in)
• Buy smaller amounts more frequently (what you'll drink in 1-2 weeks)
• Keep beans whole—don't grind until you're ready to brew

Worth knowing: Even with perfect storage, coffee peaks at 7-21 days post-roast and declines after that. "Fresh" means recently roasted, not just sealed.

Coffee Smells Weird After Brewing

What's happening: Equipment is dirty, or beans have absorbed odors from storage.

The fix:

If coffee smells musty, moldy, or off:

• Check if beans smell weird before brewing (if yes, throw them out)
• Clean your coffee maker thoroughly
• Check where you're storing beans—are they near spices, onions, or other strong-smelling foods?

If coffee smells like chemicals or plastic:

• Clean your coffee maker
• Stop storing beans in plastic containers (use glass, ceramic, or stainless steel)

If coffee smells stale or flat:

• Beans are too old—check roast date

Prevention: Store beans in an airtight container away from strong odors. Coffee absorbs smells from whatever it's near.

Simple Rules That Prevent Most Problems

1. Buy fresh beans

• Look for a roast date
• Buy beans roasted within the last 2-4 weeks
• Buy smaller amounts more often (what you'll drink in 1-2 weeks)

2. Store beans properly

• Airtight container in a cool, dark place (not the fridge)
• Keep beans whole until you're ready to brew
• Don't buy huge bags that sit around for months

3. Use decent water

• If your tap water tastes bad plain, it'll taste bad in coffee
• Filter it or use bottled water
• Don't use distilled water (makes weak coffee)

4. Measure your coffee

• Standard ratio: 1-2 tablespoons per 6 oz water
• Or use a scale: 1g coffee to 15-16g water
• Being consistent matters more than being perfect

5. Clean your stuff

• Wash your coffee maker parts weekly
• Descale every few months
• Don't let old coffee residue build up

The "Is It Worth Fixing?" Question

Sometimes your equipment is the problem, not your technique.

When to Fix Your Coffee Maker

Fix it if:

• It's less than 3-5 years old
• Cleaning and descaling helps
• It's a quality machine you paid good money for

Replace it if:

• It's over 5 years old and cleaning doesn't help
• Water doesn't heat up properly (coffee tastes weak no matter what)
• It was cheap to begin with (under $30)

Basic drip coffee makers are inexpensive to replace. Don't spend $50 trying to fix a $40 machine.

When to Upgrade Your Grinder

You don't need a grinder at all if you buy pre-ground coffee and it tastes fine.

Consider a grinder if:

• You want fresher-tasting coffee (grinding right before brewing helps)
• You're buying whole beans
• You're spending $15+ per bag on good coffee

Skip the blade grinders - they chop unevenly and heat up the beans. A basic burr grinder ($30-50) grinds more consistently.

FAQ

Q: Why is there no crema on my espresso?

Crema (the tan foam on top of espresso) comes from fresh beans and proper extraction. If you have no crema: (1) Your beans are too old—crema disappears after beans are 3-4 weeks past roast, (2) Your espresso machine isn't creating enough pressure (cheap machines sometimes can't), (3) Coffee is ground too coarse, or (4) You're using a blend that's not meant for espresso. Fresh beans fix this 90% of the time.

Q: Why does my coffee taste different every day?

You're probably not measuring consistently. Use the same amount of coffee and water every time (measuring spoon or scale). Also, if using tap water, quality can fluctuate—try filtered water for consistency. Lastly, check your beans' freshness—as they age, flavor changes daily.

Q: Do I really need to measure my coffee every time?

Yes, if you want consistent results. Eyeballing it is why your coffee tastes different every day. Use a tablespoon measure (cheap) or a kitchen scale (more accurate). Takes 10 seconds.

Q: How do I know if my tap water is the problem?

Taste your tap water plain. If it tastes like chlorine, metal, or anything unpleasant, it'll make your coffee taste that way too. Try filtered or bottled water and see if coffee tastes better.

Q: Can I fix coffee that's already brewed and tastes bad?

Not really. If it's too bitter, adding a tiny bit of salt can help (sounds weird, but it works). If it's too strong, add hot water to dilute it. But these are band-aids—better to adjust how you brew next time.

Q: My coffee maker doesn't have temperature settings. What do I do?

Most home coffee makers heat water to roughly the right temperature. If your coffee tastes weak, the problem is usually not enough coffee or stale beans, not water temperature. Focus on those first.

Q: Should I buy whole beans or pre-ground?

Whole beans stay fresh longer. If you're willing to grind before brewing (or have a grinder), whole beans are better. If not, pre-ground is fine—just buy smaller amounts so it doesn't sit around.

Q: Is my cheap coffee maker the reason my coffee tastes bad?

Maybe, but probably not. Cheap machines work fine if you use fresh beans and measure properly. The exception: if water doesn't get hot enough (coffee always tastes weak), then yes, upgrade your machine.

Q: How often should I clean my coffee maker?

Wash the carafe and filter basket weekly. Run a vinegar cleaning cycle every 3-6 months (more often if you have hard water). Most people never do this, which is why their coffee slowly gets worse over time.

Q: Does coffee really go stale that fast?

Yes. Coffee peaks 7-21 days after roasting and starts declining after that. By 2 months post-roast, it tastes noticeably worse. By 3-6 months (typical grocery store coffee), it's basically dead.

The Real Talk Section

If you've tried everything and coffee still tastes bad:

It might just be bad coffee. Not all beans are created equal. Grocery store coffee that's been sitting on shelves for months? It's going to taste mediocre no matter what you do.

Signs you need better beans, not better technique:

• Every bag from the same brand tastes bad
• Beans have no roast date, only an expiration date months away
• Coffee smells weak or stale when you open the bag
• You've tried all the fixes and nothing helps

Sometimes the answer isn't troubleshooting—it's buying better coffee to begin with.

What Actually Matters (And What Doesn't)

Matters a lot:

• Fresh beans (this is 70% of good coffee)
• Using enough coffee (don't skimp)
• Decent water (filtered if tap water tastes bad)
• Consistent measurements

Matters somewhat:

• Water temperature
• Brew time
• Equipment cleanliness

Doesn't matter as much as people think:

• Expensive equipment (a $30 French press makes great coffee)
• Perfect grind size (close enough is fine for most people)
• Fancy brewing techniques

Get the basics right first. Fresh beans + enough coffee + hot water = good coffee. Everything else is fine-tuning.

The Bottom Line

Most coffee problems come down to three things:

1. Stale beans - Check the roast date first

2. Not using enough coffee - Use 1-2 tablespoons per 6 oz water

3. Bad water - Filter it if your tap water tastes off

Fix those three things and your coffee will taste significantly better.

Everything else—grind size, brew time, water temperature—is fine-tuning. Important, but secondary to getting the basics right.

Start with fresh beans, measure consistently, and use decent water. That's 90% of good coffee right there.

Get Fresh Beans Delivered (And Stop Troubleshooting Stale Coffee)

Half the problems in this guide disappear when you use actually-fresh beans.

At Twisted Goat, we roast to order and ship within 48 hours. Every bag has the roast date printed on it. No mystery dates, no month-old beans sitting in warehouses.

How it works:

1. Order online
2. We roast your beans fresh (within 24-48 hours)
3. Ship immediately
4. Arrive at your door within days of roasting

You get beans during their peak flavor window (7-21 days post-roast), not weeks or months later.

Subscribe and they show up automatically on your schedule. Never run out, never drink stale coffee, never wonder if the beans are the problem.

Worth knowing: Fresh beans are the easiest way to better coffee. You can have mediocre technique with fresh beans and still make good coffee. But perfect technique with stale beans? Still tastes bad.