see also:

• bushwalking in Australia
• gas or liquid fuel stoves for camping
• wood stoves for camping

• Brew Ratio = brewed coffee weight / ground coffee weight
  • Brew Ratio is usually 1:2 (but can be up to 1:3) for Italian espresso which is meant to be drunk fast like a shot (its bitterness is usually moderated with sugar) thus for a single “shot” which uses 9g of ground coffee, you get 18g of coffee brew (a double shot is just twice as much coffee grounds giving 36g of brew) and traditionally use darker roasted 80% Arabica 20% Robusta blends ground to 200-300 microns and extracted with water at 90-94°C at 9 bars of pressure, which lasts around 25-30 seconds, flowing at 1-2mL/sec after the initial 3 – 5 seconds “infusion time” before you start to see the espresso extracting.
    • Ristretto has brew ratio 1:1 to 1:2
    • Lungo has brew ratio 1:3 to 1:4
    • American espresso is more dilute, milder style to allow more prolonged sipping styles often using a single origin Arabica bean which is more coarsely ground, a shot generally makes 30-50mL and uses water at 93-96°C and pressure ranging from 9-15 bars which gives a distinct flavour profile and can be served as a Long Black or diluted further to make an Americano, or it can be further improved with steaming techniques to draw out more flavours
  • Brew Ratio is usually around 1:35 to 1:4 for Moka - thus you get almost twice as much volume of brew as expresso per g of ground coffee but it is around half the concentration
• the level of extraction from your ground coffee
  • is measured as a percentage based upon weight of your brew and its total dissolved solids (TDS) measurement which is an indicator of how concentrated the coffee brew is
  • extraction percentage = brewed coffee weight x TDS% / ground coffee weight = Brew Ratio x TDS%
  • TDS% is measured using a TDS refractometer which has been set to zero by measuring distilled water, and then the coffee is measured after it is passed through a paper filter to remove solid particles
  • TDS % is g of TDS per 100g brew
  • most brews have an extraction of 20-25% but vary greatly in their concentration or TDS
  • different coffees of the same brew type will taste best with different levels of TDS
    • under-extraction results in weak and sour espresso flavours (from the tannic acid in the bean) because not enough of the pleasant flavours make it into the cup.
  • TDS may be altered by many factors such as differences in harvesting, blending and roasting of the coffee beans, grind size, starting water volume and temperature in the case of a Moka
  • Turkish coffees are the most concentrated
  • Italian Espresso coffees are very concentrated as they use very high pressures to push water through very finely ground coffee and generally have a TDS of 8-12 and an extraction of 22-25%, plus the high pressures used create the characteristic crema on the surface
  • Moka coffees use a more coarse grind and at lower pressures and are about half as concentrated as expresso and have TDS of around 3.5-4.5
  • AeroPress Prismo higher pressure brews have a TDS similar to Moka of 3.5-5%
  • AeroPress and French Press coffees have a TDS of around 1.4-1.7
  • Pour Over brews use the most coarse grinds and just gravity as pressure and have a TDS of around 1.2-1.5
• NB. TDS can be also used to measure the quality of the water you are using to make your brew, in general, this TDS should be 75-250 mg/L (ppm) for brewing water, with an ideal target of 150 mg/L

• buy ready made cappucino sachets, just add hot water and stir, no need for added milk

• great for simplicity, price, ergonomics and durability but low pressure 1 to 2 bar (100 to 200 kPa) so minimal crema and not as concentrated as an espresso
• NB. you can get stainless steel moka pots which work on induction stoves as well as other stoves, but the flavour is not as nice as with aluminium pots (if you need to use an induction cooker, you can get aluminium pots with stainless steel base plates to help resolve this such as the Bialetti induction moka pot, or you can get an induction plate to put under your aluminium pot)
• ensure you have the best size for your need - 1 “cup” equates to ~40mL of brewed coffee and uses about 5-10g ground coffee per cup
• while espresso has a brew ratio of 1:2, moka pots come in at about half as strong
  • if making a cafe latte, you will need 2 “cups” worth from a moka to give similar “strength as 1 shot of espresso, thus, a 2 cup pot may be the best for one person, and a 4 cup for two people
  • if you want an Americano, use a 4-6 cup moka pot for 1 person (gives about 180-240mL brewed coffee and then top it up with hot water), or 9-10 cup pot for 2 people
  • you can use half the amount of water and half the amount of coffee in a moka pot if you only want half as much, but you shouldn't go less than half
• stove top “moka” pots REQUIRE a grind more coarse than espresso but finer than pour over coffee brews, and similar to an Aeropress grind
• ideally you will bring a portable grinder and reasonably freshly roasted coffee beans in a sealed container that is kept out of the sun and NOT in the fridge
  • you need 20g or just under a 1/4 cup of coffee beans to fill a 3 cup (150mL base) Moka pot (or a 4 cup Bialetti induction)
• need to follow the process:
  • add water:
    • for light roasted coffees:
      • add hot (NOT boiling) water to just under the level of the valve
    • for dark roasted coffees:
      • add room temp water 20mL less than the level at the valve - this will give a higher TDS but overall less extraction and less volume brew ¹⁾
    • ensure valve is functional by pulling it out against its spring with fingernails
    • NB. an extraction ratio of 22-23% is perhaps ideal for Moka pots - going over 25% brings it more unpleasant flavours it seems
  • coffee grinds to fill the coffee chamber evenly to the top without leaving air spaces but must NOT be tamped, use a dry brush to remove grains on the screw thread
  • coffee chamber must be perfectly sealed without dents as these will allow steam to bypass the coffee and you will just get water in the percolate
  • top part of the pot must be firmly screwed in place to ensure optimum seal
    • inadequate seal results in water and steam coming out of seal, and ineffective coffee brewing with lots of premature splattering
    • ensure no coffee grains on the thread
    • the rubber seal may need replacement if worn
  • heat should be medium only to avoid too rapid a percolation process
  • ideally, heat the pot with the lid OPEN WHILE CLOSELY WATCHING IT - as soon as the coffee starts to percolate, reduce the heat to prevent too rapid a process, then take it OFF the heat just before it finishes percolating otherwise it will splash everywhere and your coffee flavor will be impacted
  • Do NOT unscrew base while still very hot as sudden release of pressure may cause scald burns!
• trouble-shooting too much steam and spluttering at start causing poor extraction
  • don't tamp the coffee!
    • tamping creates too much resistance for the low pressure in a moka pot, forcing water to find the path of least resistance and causing uneven extraction. Instead, fill the filter basket with coffee and gently level it out, perhaps with a light shake or tap—never compress the grounds
  • use the correct grind size
    • The ideal grind is slightly finer than table salt but coarser than espresso. Too fine a grind can compact and block the flow, again leading to channeling. Too coarse, and the water passes through too quickly, under-extracting the coffee. Avoid blade grinders, use a burr grinder for more even grinds.
    • eg. Femobook A2 lithium powered grinder use grind setting 6 seems to work very well
  • ensure even coverage of coffee
    • After adding coffee to the basket, gently shake or tap the basket to distribute grounds evenly. Some users recommend using a distribution tool (like a WDT—Weiss Distribution Technique tool) to break up clumps and ensure an even bed, but avoid pressing down
  • ensure basket is dry before adding the coffee
    • A wet basket can cause grounds to stick unevenly, leading to an inconsistent bed density and increased risk of channeling. Always dry the basket thoroughly before adding coffee
  • clean the pot regularly
    • Blockages in the filter or buildup in the pot can disrupt water flow, creating uneven pressure and contributing to channel formation. Disassemble and clean all parts, especially the filter and silicone seal, to maintain optimal performance
  • use gentle heat
    • Apply a low to medium flame or heat source to avoid rapid pressure buildup, which can exacerbate channeling and lead to sputtering or uneven extraction
• standard aluminium moka pots
  • ?2 cup uses 150mL water in base to output ?120mL coffee using 20g or just under a 1/4 cup of coffee beans
• Bialetti induction moka pots
  • 2 cup uses 130mL water in base to output 100mL coffee using 15g coffee (output may vary 80-100ml depending upon method) diameter top of base is 56mm
  • 4 cup uses 180mL water in base to output 150mL coffee using 20g or just under a 1/4 cup of coffee beans, diameter top of base is 63mm
  • 6 cup uses 320mL water in base to output 280mL coffee
  • need to avoid channels forming in the coffee:
    • use nearly boiling water to start with to just under the release valve
    • portable Femobook A2 lithium powered grinder use grind setting 6, and ensure even spread without tamping it down
    • gentle heat, eg. setting 5 of 12 on a kitchen induction stove until it starts percolating out then drop to 3
    • if onset of percolating is associated with lots of steam and spluttering then you have channels forming and your coffee will not be great and it will be of low volume

• incorporates a weighted valve as a pressure regulator on top of the nozzle that allows pressure to build up inside the water tank in a manner similar to a pressure cooker.
• As pressure builds up more quickly in this method (since there is much less leakage of vapour) compared to the standard moka pot, it reaches the level required for water to rise through the ground coffee in a shorter time. However, the weighted valve allows pressure to accumulate and temperature to rise somewhat further before the liquid bursts through the nozzle.
• The result is coffee brewed at a higher pressure and temperature than the standard pot, making it more similar to espresso and therefore with more visible crema, but still not the same as a pumped espresso.

• hard anodised aluminium 2-3 cup (350mL) with a dripping spout and silicone detailing
• cons:
  • 3x price of a moka pot
  • spout is likely to be damaged unless unscrewed but doing so risks losing the tiny plastic washers
  • no handle and the silicone is not wide enough to allow safe handling while hot and the unit remains hot for quite some time necessitating the use of oven gloves to handle (although theoretically it does fit inside a Furno camp pot so this may be a workaround)
  • dripping coffee sprays all over the place in windy conditions
  • rubber gasket fits loosely on the filter mesh and is annoying to re-fit each time
• personally I would not recommend for camping despite it looking cool

• https://www.wacaco.com/pages/collection/#nanopresso
• incorporates a manual pump to give a maximum of 18 bars (261 PSI) of stable pressure during extraction
• works best with finely ground coffee that is tamped hard
• 80mL boiling water must be added to chamber
• 336g
• optional NS Adaptor for Nespresso-type pods

• https://www.wacaco.com/pages/collection/#minipresso
• NS version uses Nespresso-compatible pods
• GR version uses ground coffee
• incorporates a manual pump to generate 8 bar which is sufficient psi to give crema
• uses 70mL boiling water
• 350g
• I would recommend doing 1 or 2 runs with boiling water without coffee to heat it up so your expresso is not too cold

• https://aeropress.com/
• perhaps the best option as it is light, easy to clean, unlikely to break, relatively compact and simple to use to make a reasonable espresso or Americano but you won't get crema
• only 226g and is 14x11x10cm (excluding paper filters and filter holder and funnel
• works best with finely ground light roast coffee (but grind should be similar to moka grind, coarser than expresso and finer than pour overs) and there are many recipes such as:
  • Espresso:
    • as per Aeropress directions, 1 heaped spoon (14g) add 80degC water to the 1 marker, stir for 10sec, then insert plunger and plunge gently
    • if making a cold brew do the same but use cold water and stir for 1 minute not just 10secs
    • convert hot espresso to Americano by adding hot water to fill a 237mL mug
    • convert hot espresso to Latte by adding hot milk to fill a 237mL mug
  • Americano:
    • James Hoffman's fine ground “ultimate” method:
      • 11g coffee, add 200g water at around 95degC (90degC for medium roast and 85degC for dark roast), ensure you put the plunger in immediately to create a vacuum and allow time for the water to extract from the coffee for 2 minutes then gently shake to allow floating coffee to settle, wait 30secs then very gently plunge
      • James Hoffman's ultimate recipe for Aeropress
    • coarse ground inverted methods
      • 30-35g coarse ground coffee onto the plunger which is inside the inverted tube
      • initial 100g 80-94degC water
      • stir vigorously for 10-20sec
      • add further 100g water either at this point then stir again for 10secs or as a dilution later
      • total brew time 60-100secs
      • add the rinsed paper filter and filter holder
      • invert then plunge
      • allow to cool to 60degC
• optionally match it with a hand grinder that fits inside it such as the:
  • Knock Aergrind
    • see James Hoffman's review
• if you have money to spend and more space and don't mind more weight, consider the 1Zpresso JX-Pro or the very expensive Kinu M47 hand grinder

• these may be preferred for larger groups and those with wood stoves for camping
• Winnerwell 14 Cup Stainless Percolator Coffee Pot / kettle Tentworld $AU96

• roasting the beans
  • slower roasts tend to minimise the unwanted movement of oils to the surface of the beans where they would be exposed to oxidation and rancidity
• degassing the roasted beans
  • https://perfectdailygrind.com/2019/01/why-does-coffee-degas-what-does-it-mean-for-brewers-roasters/
  • https://europeancoffeetrip.com/coffee-freshness-science/
  • most taste better when allowed to degas for 2-5 days after roasting - the optimum time depends on a range of factors
    • natural coffees need longer times to degas than washed
    • a dark roast accelerates degassing because the bean has degraded more
  • using it too soon after roasting, the very high CO₂ levels prevent the percolating water interacting with the ground coffee, this is particularly an issue with short brew times such as when pulling an espresso, but less of an issue with longer brew techniques
  • too much degassing results in less vibrant flavours (labile coffee aroma escapes with time and combined with exposure to UV light and oxygen which can degrade the coffee oils making them rancid and stale and this process is faster at higher temperatures and at higher humidity) and less crema
    • chemical freshness relates to the aroma changes in coffee
      • coffee consists of perhaps 40-50 key aromas, each behaves differently, and often the same compound can have a positive and negative smell attribute, which changes only with its concentration
      • for each coffee, there will be a different peak concentration of each of these aromas for the optimum experience. The extraction method plays a role, and the optimum might be different if we use the coffee for espresso or for filter coffee
      • for instance after 2 weeks, there may only be 20% of the methanethiol left and 80% of the methylpyrazine left
      • storing coffee in the freezer will prolong the coffee freshness for about 10-times, but it should be within a sealed container so that humidity and smell from other food in the freezer does not migrate into coffee beans. When using, allow 1-2 hours for the container to reach room temperature before opening.
    • physical freshness relates to the degassing changes
      • 1% of freshly roasted coffee beans consist of CO₂ and it takes 1-2 months for this to be fully released
• grinding
  • coarsely ground beans retain more gas and provide more crema but may have less flavour
  • a high pressure true espresso machine requires very finely ground coffee
  • the sooner it is brewed the better
  • it can be stored up to a week in a sealed container at low temperatures but longer storage should have vacuum sealing or similar
  • plunger coffee machines or percolators generally require coarse ground coffee however the Aeropress works best with finely ground coffee similar to espresso makers
  • very finely ground coffee tamped down increases the contact time with water as well as surface area but needs more pressure (eg. 9 bars) and runs the risk of channels forming creating increased bitterness due to localised over-extraction
  • too coarse and one may have sour coffee, too fine and it may be too bitter
• making the espresso coffee
  • 9 bar (900 kPa) is the usual “ideal” pressure (range is 8-18 bars) with water at 91–95 °C to make an espresso coffee hence moka coffee at only 1-2 bar is not really espresso and has a different flavour characteristic to espresso

• Youtube quick tutorial on crema
• crema is the brown foam on top of the espresso which is formed from the release of carbon dioxide from the roasted coffee beans into the pressurised steam (low pressure moka pots tend not to form much crema) which is released from the de-pressurised water as it percolates up and then trapped as bubbles within a surfactant created by melanoids and other hydrophobic lipid molecules
• the crema tends to have the most bitterness and this is in part to it often containing coffee bean particles, and many prefer to scoop it off
• crema tends to be a sign of a well made espresso
• crema is maximised by:
  • high pressure percolation
  • coffee grinds with high CO₂ content:
    • robusta beans (~3x more CO₂ than arabica beans) which have been roasted longer (eg 15 minutes instead of 5 minutes) and darker
    • coarse ground grinding rather than fine ground
    • room temperature degassing rather than 40degC degassing
    • freshly roasted (after 3 days degassing) coffee and freshly ground