A couple of quick newbie questions.

Using a Breville Oracle, I have been able to get a consistent dose (18g / 17.8-18.3g) from the grinder by adjusting the tamp fan height. However, the shot weights that gets extracted from these are highly variable for each grind setting. It varies from anywhere from 30g to 45g for the same standard 30 second shot. Is this normal? I like the coffee at ~36g the best (although it is still a bit sour -- see below), while 40g+ is bitter as expected. Is there something I can do to reduce this inconsistency? Or is my only solution to always use my AWS scale below the cup, and stop the shot manually at exactly 36g?

So, as above, even the best shots are a bit sour. I used this chart:


I tried changing the tamp pressure and tamp seconds setting on the machine to make it lighter, but still got sour-ish shots. Tried to extract it a bit longer, but it became more bitter. How do I fix this? I don't want to spend more (or make things even more complicated) by buying new grinder, etc.

Also, the coffee bean I'm using is supposed to be "mildly acidic." What does that mean? Is it possible that I am confusing acidic with sour?

Thanks in advance!

Welcome to HB!

Disclaimer - I am no expert, so I am sure others will offer additional or better advice. I am not that familiar with the Oracle, as I have the Breville Dual boiler, but my overall advice is to reduce the number of variables you are changing, until you get shots that are tasting right.

Here is what I would do:
- It sounds like you have a pretty consistent coffee dose - that's a good start!
- I don't know how consistent the Oracle is with timed shots, but regardless in the short term I think you need to eliminate this as a variable. I would do exactly what you suggested, which is manually stop the shot at 36g. That way, you know your initial weight (18 grams) and final drink weight (36 grams) are consistent shot to shot.
- I also don't know how the tamp pressure setting/seconds works on the Oracle, but I wouldn't change that to begin with. I would return that to the default setting.
- What coffee are you actually using? It sounds like it is one your aren't that familiar with. I would recommend starting with one that you know how it should taste. It's really hard to learn a new machine with a new coffee as well. My advice is start with a coffee that is medium roast or darker. It's going to be easier to dial in as you get started. Tons of recommendations on this board for more traditional roasted coffee that are easy to dial in.
- What is your brew temperature set at? Someone can probably recommend a temperature once we know what beans you are using.

Once you are working with a familiar coffee and have the temp set, start pulling your 18g in/36g out shots and see how they taste. Then, the only variable I would adjust if if needed is the grind setting. If it's too sour, grind finer. If too bitter grind coarser. If you are using a forgiving coffee, that should get you within range of an acceptable shot. As you get more experienced, it will be easier to adjust additional variables. For now, keep it simple!

By using the search function on the top of this page, you'll find some discussions on somewhat similar issues.
Many seem to suggest that you shouldn't use automatic features, but operate the machine manually.

Also (you won't like this) it seems recommended to get a better grinder. It makes sense since a good grinder is the key to good espresso. If a grinder isn't up to the task, there is no way around it but getting a new one.

cuppa wrote:Also, the coffee bean I'm using is supposed to be "mildly acidic." What does that mean? Is it possible that I am confusing acidic with sour?

Coffee has a mix of many acids depending on various circumstances. Acids are a complex thing. For example a good amount of citric acid can taste sour (like lemon or strong vinegar), but many other acids won't. Think of carbonic acid, mixed with water it doesn't taste sour at all, but instead you can feel it in your mouth.

There is a good article on acidity in coffee. It is worth reading: https://www.fivesenses.com.au/blog/acad ... id-coffee/

What basket are you using for the 18 g dose. If it's the one that came with the machine then I suspect that this may be part of the problem .it is designed for 22 g , this could be causing channeling etc
From personal experience Re consistency , use scales, the machine can't deliver a consistent amount in the cup. Between the poor grinder , beans heating up on the top and the way it tamps. Lastly it is not a several 1000 dollar volumetric machine and can't be expected to deliver as such. This is before we potentially take into account that you may be massivley under dosing the basket.

You could be confusing acidic with sour of course .playing with tamp pressure isn't going to solve this imho.

Mrboots2u wrote:playing with tamp pressure isn't going to solve this imho.

+1

Tamping pressure hardly is the source of the problem: http://socraticcoffee.com/2015/07/the-i ... xtraction/

Thank you all for the detailed replies, they were very helpful!

In fact, Mrboots2u, you completely nailed the inconsistency issue. I thought I was not having channeling issues as I did not visually see any channels, but clearly I was having them because once I adjusted the dose back up to 22g, shot weights have been much more consistent!

Iowa_Boy, I was using a local roast that I was not completely familiar with as I had run out of george howell alchemy espresso, but I have ordered some this morning. Hopefully that would help! Brew temp is 200F. I'm a bit confused by this statement of yours:

If it's too sour, grind finer. If too bitter grind coarser.

Shouldn't it be the other way around? If the later/blonder parts of the shot are what gives it the bitter taste, shouldn't I allow less water to flow through it (grind finer)?

cuppa wrote:Shouldn't it be the other way around? If the later/blonder parts of the shot are what gives it the bitter taste, shouldn't I allow less water to flow through it (grind finer)?

Usually the advice goes:

Too sour - lower the dose and grind finer
Too bitter - increase the dose and grind coarser

That way you don't change the extraction time.

BUT, if you grind finer without altering the dose you will increase the extraction time in order to get the shot ratio you're aiming for. If time is too long you enhance the risk of channeling which will cause under extraction. The longer the time, the better the basket preparation has to be.

When extracting coffee the main factors are: grind, temperature and time. With espresso comes also pressure, but let's not go there yet.
If your coffee is under extracted you can fix it by grinding finer, raising the temperature or increasing time. If your coffee is bitter then it works the other way around. If you want to keep a certain ratio and alter time, then you'd have to do it by changing the grind. Personally I don't focus on time too much. I like to keep it in certain time window (let's say for example 35-40s when using Nordic roasts).

Barista Hustle website had a great series of articles on espresso extraction if you want to go and dig deeper.
https://baristahustle.com/blog/ (search "espresso recipes")

Thanks again. So, keeping things a little simpler, if I don't change the dose (22g) or the extraction time (30s), what would happen if I grind coarser or finer? My understanding is that grinding coarser (keeping the other two the same) would make the espresso more bitter (and less sour) since more water will flow through in the same unit of time, and grinding finer (keeping the other two the same) would make the espresso more sour (and less bitter) since less water will flow through in the same unit of time. Is that accurate?

Thanks for that link too!

cuppa wrote:if I don't change the dose (22g) or the extraction time (30s), what would happen if I grind coarser or finer?

You would get more (by grinding coarser) or less (grinding finer) coffee to drink. Then you'd change the ratio. It is a good way to find a good extraction to go for a certain ratio (1:2 is quite typical) and dose and then try to get to a certain time window with changing the grind. From that point you could fine tune your shots by the taste. Usually roasters give a guideline for espresso recipes. Naturally, since tastes are different the guidelines are only guidelines and can be changed as much one wants.

cuppa wrote:My understanding is that grinding coarser (keeping the other two the same) would make the espresso more bitter (and less sour) since more water will flow through in the same unit of time, and grinding finer (keeping the other two the same) would make the espresso more sour (and less bitter) since less water will flow through in the same unit of time. Is that accurate?

Nope, it's quite the opposite, as I said earlier:

Nick Name wrote:Usually the advice goes:

Too sour - lower the dose and grind finer
Too bitter - increase the dose and grind coarser

I don't know how did you got the idea that it would be the other way around, but it's not. Grinding finer lowers sourness and grinding coarser lowers bitterness. I think that is the most basic thing when dialling in for espresso.

I suggest you focus on keeping a certain ratio and try to get good coffee with it. If you have a precision basket (if not, you can get one) use the dose it is optimised for. Then change the grind (and also the time of course) by the taste (too sour vs. too bitter). If you have ground finer and your espresso still tastes sour even the extraction time exceeds way over 40 seconds (or it chokes your machine), THEN lower the dose accordingly.

More water results to a more watery shot, less water results in a more concentrated shot. Flow isn't THAT important with espresso. You'll get better results if you focus on the grind (or temperature if you can).

Pump pressure and flow rate do affect espresso extraction, but as Barista Hustle puts it well:
"That's a rabbit hole we really don't have time for today." (and that is meant for more or less professional baristas)

So, forget the flow for now and focus on the more important factors. I think you may be overthinking it a bit too much. It is actually quite simple.

1. Keep the ratio
2. Change the grind
3. Keep the dose as long as you can

Don't forget that the temperature plays a part as well, but only change one factor at a time. Learn to trust your taste and make changes according to it.

If you get bland coffee (from freshly roasted beans) then you may have gone too far with grinding finer. There is a point that shouldn't be crossed over. That depends on many things and it is not a set point. You will taste it though.

The beans you're using make a huge difference in how you should dial in. Dark roasts are more prone to taste bitter and light roasts are more prone to taste sour. For light roasts it is ok for the extraction to take longer than the traditional espresso guideline 25-30s.