shawndo wrote:Instead of setting it by the flow rate (i.e. 40g/30sec) I adjusted it by the amount of time it takes to fill the headspace and for the gauge to start climbing. I set mine so that group pressure gauge starts climbing at around 10 seconds to match the Slayer I sampled.
This is faster than the default Slayer settings but works well.

Do you find that there's a general dose/headspace/basket combo heuristic that you follow?

I myself am trying to nail the headspace/flathead dispersion screw indent balance. Any tips?

For dose, I either use the ol' reliable nickle test (i literally keep a nickle next to the espresso machine) or I just keep updosing until the it starts doughnut-ing in a bottomless or I notice it is obviously overdosed by looking at the puck after the shot. There are probably smarter people with better ways to choose the dose on here.
I know some do it by taste but there are so many things to adjust by taste, i try to minimize those as much as possible so I'm only adjusting one parameter by taste.

There is a good couple of videos on dialing in a recipe (dose/yield/etc) but I'm still not putting it into a systematic practice. It's on the todo list
https://baristahustle.com/blogs/barista ... l-together

shawndo wrote:For dose, ... I just keep updosing until the it starts doughnut-ing in a bottomless.

Do you often see doughnut extractions when there's not enough headspace? I can't recall reading any mention of that relationship, and have a hard time imagining why doughnut extractions would be more likely with insufficient headspace. I can certainly see lack of headspace causing the puck to break up, but in that case I'd expect random channeling, not necessarily doughtnut extractions.

My thought has been that the doughnut extractions I get are caused by the grinds from my Monolith Flat building a mountain in the center of the basket -- i.e., there's a lot more coffee in the center than at the edges, even after I push coffee around to fill in the edges and level the top. To solve that problem, I leave a large divot in the center of the grounds when I WDT, then use a modified Sockfleths' move to push coffee to the edges while putting as little as possible in the divot. About 80%-90% of the time this results in first drops across the entire bottom of the basket at the same time. I've thought that the other 10%-20% of the time that I get doughnut extractions I wasn't quite careful enough about keeping grounds out of the center.

If your theory is right, it'll save me lots of time/effort. I've been dosing 18.1g in an 18g VST basket. I've never used the nickel test, but if I insert and remove the PF I always see a slight impression of the dispersion screw. I'll bet a nickel would sink to it's full depth. I guess I'll have to try a 17g dose and see what happens. Below that, I'll have to try a different brand of basket.

Peppersass wrote:Do you often see doughnut extractions when there's not enough headspace?

I can consistently clear up doughnut problems if I lower the dose, but i think this is just a correlation and not a definitive proof of the cause. Maybe its my low profile screw/screen or something. Not sure.

This has been true though my complete grinder/machine history (except for the unaligned Versalab. No clearing that up without the FrankMod)
I know I've seen debates on this topic more than once on the forum on how to address doughnuts and i got the idea to lower the dose from a post on here somewhere so I think it has been mentioned.
I use the WDT and also leave a divet it in the middle with the needle before tamping to counter the center pile dense-ness. I've done this for every grinder I've had also, not just the Monolith.

I'm sure I do a ton of things I just got used to doing over the years and might not have any actual effect.

shawndo wrote:There is a good couple of videos on dialing in a recipe (dose/yield/etc) but I'm still not putting it into a systematic practice. It's on the todo list
https://baristahustle.com/blogs/barista ... l-together

I generally agree with the precept that you should choose the dose based on the amount of coffee you want to make, and that for a given beverage amount, say a double, you should keep the dose constant regardless of the coffee. And that's what I tend to do -- I usually stick with 18g doubles.

However, the dose=size theory breaks down in certain situations due to the relationship between dose and grind, and the significant impact a change of grind has on flavor.

For example, say you've dialed in a 14g double yielding 28g and want half as much coffee. So you go to a 7g single yielding 14g of beverage. But the reduction in dose requires a much finer grind to achieve the same flow rate. While in theory the same flow rate should produce the same flavor, the finer grind will significantly change the flavor (sometimes to the good, sometimes not.)

One way around this is to dose according to the square of the hole area ratio of the baskets. For example, if the square of the hole area ratio of the single to the double is 60%, you would dose about 8.4g for the single without changing the grind. In that case, to get the same brew ratio you have to pull 16.8g, a little more coffee than you wanted. Here's Jim Schulman's post on how to do it (for some odd reason this is the third I've posted this link this week!)

Another common situation where the dose=size theory breaks down is updosing to compensate for a dark roast or downdosing to compensate for a light roast.

And some may recall Jim Shulman's posts admonishing us to change the dose, not the grind, when the flow rate changes due to changes in the coffee, like aging. Jim's theory is that by changing the dose you can maintain the same flavor, which won't happen if you change the grind. You can search for that series.

I think for most of us non-gifted tasters it's probably OK to stick with a constant dose in most situations. But to get the ideal extraction that will wow a super-taster, it may be necessary to adjust the dose.

thanks for the advice on the divot, going to try it tomorrow morning

theres a bit less dosing flexibility with the Vivaldi baskets; I'm generally using the ims triple basket for doses at 18+gs, no impression in the puck and no cracks, but a bit of a donut at the start of the pour from time to time which I don't think is related to too much coffee in the basket generally; my ims double starts to get tight at 18gs

Peppersass wrote: <snip>
However, the dose=size theory breaks down in certain situations due to the relationship between dose and grind, and the significant impact a change of grind has on flavor.

For example, say you've dialed in a 14g double yielding 28g and want half as much coffee. So you go to a 7g single yielding 14g of beverage. But the reduction in dose requires a much finer grind to achieve the same flow rate. While in theory the same flow rate should produce the same flavor, the finer grind will significantly change the flavor (sometimes to the good, sometimes not.)

Generally, when using the IMS single baskets (all things 58mm basket related ), I find I can down dose without adjusting the grinder setting.

shawndo wrote:There is a good couple of videos on dialing in a recipe (dose/yield/etc) but I'm still not putting it into a systematic practice. It's on the todo list
https://baristahustle.com/blogs/barista ... l-together

What a great find! I've watched it 3-4 times already and read the articles associated with the video and am going to try that system for the next few weeks. I've been out of the game for a few years and need a solid system to get back in. In reading through other parts of his blogs, I noticed he said the Robur-E (which was my previous grinder) can require 100gm of flush after every grind change!

Back to your post's subject, do you know the flow rate of the Slayer? I wonder because I can change the flow rate of my pre-infusion very easily.

mitch236 wrote:Back to your post's subject, do you know the flow rate of the Slayer? I wonder because I can change the flow rate of my pre-infusion very easily.

Mitch, the needle valve used to restrict the pre-infusion flow rate in the Slayer can bet set by the user to just about any flow rate below the pump speed -- down to almost nothing. Slayer recommends setting it to a rate of about 80ml/min.

Slayer also recommend shooting for 20 seconds of pre-infusion, which they define as the time from start to immediately before the espresso flows consistently from the bottom of the basket. Not exactly sure what that means, but the instructions say it's after drops begin to appear on the bottom of the basket.

Here's a link to the Slayer manual

I know an owner who favors 15 seconds of pre-infusion for most coffees.

Of course, you can adjust the pre-infusion time via the needle valve or the grind setting.

The 3 BAR setting for the Hydra bypass you mentioned to me in a PM strikes me as too high, though it depends on other things like the size of the gicleur (if any.) I have to set my line pressure to 1-2 BAR to get a Slater-like shot from my GS/3 with gear pump.

Having the weekend to play with pre-infusion has taught me one thing, it doesn't work for my machine! I could slow down my flow during pre-infusion to 80mL in 45 seconds. However, this caused my shots to be underextracted and the flow always began at the perimeter. I guess the slow flow was allowing the puck to lift slightly and lose it's seal with the basket. Once I returned the machine to it's stock setup of 2.5-3 BAR of pre-infusion, everything got much better. I tried grinding so fine that shots were taking almost 2 minutes to complete. Either there's more to Slayer's pre-infusion flow that I can't mimic or I'm not doing a good enough job of shot prep. Either way, I plan to stick with what works.