I recently got the VST 18 and 22g baskets in and have been working with them a little. I also just recently installed a La Marzocco GB5 2 group Paddle. The only experience I have with pre-infusion was on a Synesso Hydra a couple years ago. I have a couple questions and welcome any other advice or comments related to the subjects.
With the VST baskets, I am pulling Hairbender at about a 20g dose. In the 18g baskets, it leaves very little (if any) room to the screen. With the 22g baskets, there is a lot of room to the screen. Is it possible to have too much room? What kind of experience does anyone have using the VST baskets? I notice right away that the quality seems to have a wider range for a good to great shot. But, I have yet to pull a shot that has made me entirely confident in the switch. Any thoughts?
With the Paddle and pre-infusion, it seems like I can let it run for 20 seconds before the first drops come out. Is there a desired pre-infusion time on these machines? With the Synesso, It seems like within 5-7 seconds or so the first few drops would come and we would activate the pump. The espresso we pulled was incredible. Any advice for pre-infusing on these?
Also, we are using Hairbender 5-10 days out. We are pulling, generally, 1.5oz shots +- .25 oz. I love finding opportunities to learn and grow as a barista and trainer and welcome any constructive comments you may have! Thanks in advance!!!
Little experience using VST baskets (played a bit yesterday) and been a while since I played with the MP, but that sure sounds like a long, long, long time for first drops. I think you are smart to preinfuse the same as you did on the Synesso for a starting point. Definitely try to get beading a little more quickly.
Headspace is a variable to be messed with. Different coffees will expand differently, and this is relevant. That said, seems like 20g is too much in the 18g basket.
What is your incoming line pressure, by the way?
Incoming line pressure is 3 bars, should have mentioned that. I have read about 20-30 second pre-infusion times and that just sounds crazy. I should run a few and time them for reference.
I have heard of a lot of people getting frustrated with the VST baskets and going back before dialing them in properly. I have also heard enough people that finally do make the proper adjustments and can't imagine going back. I do want to make sure I am pulling better shots with the VST's before serving them, but I definitely want to dial them in before making any decisions.
Also, since we are using E model Mazzers, we haven't been grooming prior to tamping in the old baskets. From what I read, with the VST baskets you want to have a flat surface before tamping since the holes are closer to the edge. I have been settling after ever-so-slightly shaking the portafilter to level the grinds before tamping.
I had the chance to talk to Vince Fedele at SCAA and have been using VST/Strada baskets for a while now, so I think some other insight is necessary before addressing the outcome. A quick note, if you have a scale that works in .1 gram increments I highly highly highly recommend using it in conjuction with these baskets. It makes diagnosing adjustments and recording/analyzing results incredibly easy. Volume just varies too much depending on how far off roast you are.
VST baskets are recommended for a 1 gram variance around the dose they are graded for, and I have not experienced good results going out of that range. That means you should be dosing 17-19 grams in the 18g baskets, 21-23 in the 22g basket.
They also, because of uniform hole size, have a very limited grind variance. Where this is on your grinder depends on a number of factors.
So having said all that, the VST baskets are designed to be used in a very specific way: brewing coffee at ratios of 66, 50 and 33%. These ratios are calculate by dividing the amount of coffee you use(say, 18g) by the weight of the shot you produce(say, 27g for a 66%, or 36g for a 50%).
I recommend playing around with the different ratios, seeing what you like best with hairbender, writing down as much data as you can on shots you like and don't like and see what you can implement from the experimentation into your training.
One last thing: because the VSTs have a constant resistance on the bottom of the basket, and, by correlation, want to have a consistent flow rate through the basket, make very careful not to center dose the basket as is necessary on a lot of other manufacturer/OEM baskets. You will get a slower flow through the middle of the puck and faster flow/channeling on the outside of the puck. It can take some time to get used to filling the basket differently, and coffee will taste poor until you do, but once you are able to execute even distribution from the grinder, it will make a world of difference.