Volumetrics – For A Linea PB (Part 3)
The Linea PB take a different approach when it comes to programming. It uses a menu system and has two doses per button, rather than 4 buttons with individual doses. We can use the traditional style of programming outlined in part 2 of this series, or we can view and edit the doses using the pulses that our flow meters speak in. This is useful for a couple of reasons – it allows you to be more accurate and faster in your adjustments, requires less coffee wastage, and can help you fine tune groups that are running a bit longer or shorter than desired. Here’s a few things you need to know before you get started:
- The left group is still the boss. Holding the swirly button will take you into the menu. You can’t run shots while you’re in menu mode, so make sure you’re doing this while you’re quiet!
- When you’re in menu mode, the 1 cup button will cycle you through the menu to your left, the 2 cup button to the right, and the swirly button is an ‘enter’ key.
- Pressing the 2 cup and the swirly button together will take you out of the menus and back to the regular screen, where you can make shots again. This is great if you end up in a part of the menu that’s confusing, or if you need to quickly get out to run a shot!
- Make sure when you weigh your brew water you do it without the handle in – you don’t want any water hiding from you!
- Our volumetrics may require a different number of pulses to give you the same amount of water – this is totally fine! This may be more evident on the PB because you have a numeric measurement.
- Use the PB pulse predictor. It’s amazing. You can find it here: http://coffeekaizen.com/linea-pb-pulse-predictor/
Alrighty! With all that out of the way, lets break this down step by step.
- Before we get into menu mode, we’re going to weigh our current yield on the left group. Dial your grinder in to 0.1g and +-2 seconds from the recipe, then run a shot and weigh your yield (off both spouts!). Write this number down.
- We need to work out if our groups are the same. Weigh the brew water for the left group, write it down and then repeat the process for the others. It’s fine if they’re different, but it’s best to know now.
- Time for menu mode! Hold down that swirly button on the left group for about 5 seconds. The first option will say ‘group dose settings’. Enter that menu using the swirly button. The next menu will say ‘program volume dose’. This option allows us to program the volumetrics like a regular machine. Click right through the menu using the 2 cup button, which will give you an option that says ‘view and edit doses’. Click the swirly guy to enter this menu.
- Alrighty! This is where things get real. This menu level is set up to run through consecutively – the first option will be group 1 button 1 (G1B1), meaning the 1 cup button of the left group. If you go right (2 cup) from there, it will give you G1B1 long dose. The next option will be G1B2, then G1B2 long dose, then G2B1 and so on and so forth.
- The numbers next to each button option are ‘pulses’ of the flow meter – how many times it is spinning. To change this number we hit the swirly button, which will make the numbers flash. To have less water, use the 1 cup button to reduce the number of rotations. To have more water, bump the pulses up using the 2 cup button. Pressing enter again will lock that number in and stop it from flashing.
- But how much do we need to change them by?! This is where the pulse predictor comes in handy. Now that we have the complete set of info we’re going to punch those numbers in. Dose comes first, then current yield, and finally the current pulses. If you scroll down, you can then enter your desired yield, and the predictor will estimate how many pulses that will take. Hold your swirly button and adjust the pulses accordingly.
- Now it’s time to check! The larger the difference is in your current and desired yield the less accurate the predictor is, unfortunately. Fine tune the left group first, by running a shot and checking the yield. If it’s correct, happy days! If not, punch the numbers back into the predictor and adjust accordingly.
- Now it’s time to do the others! If all the brew water weights were initially the same, adjust the pulses on the other groups to the same number. If you have different numbers of pulses but the same amount of water, keep the difference the same (eg G1B1 was 330 pulses delivering 70g of water, but G2B1 was 340 pulses delivering 70g of water, the difference is 10). Conversely, if the groups have the same pulses but are giving different amounts of water (330 pulses giving 70g BW, and 330 pulses giving 65g BW), the most accurate way to correct this is repeating the whole process for that group and using the calculator again.
- Finally, we want to check all our groups. The fastest way to do this is taring that cup off again and weighing the brew water. Write it down. Then check the other groups – we want the brew water weight to be within +-1.5g of each.