# Effect of temperature at different stages of pour over brewing



## bpchia (Dec 23, 2014)

Hi all,

With the usual disclaimer that the ideal temperature for brewing depends on lots of factors including perhaps from most important to least important the roast profile, bean, brew method, agitation, etc....I'm wondering if we can discuss the effect of temperature that a pour over kettle (or automatic brewer for that matter, very keen on Scott Rao using the DE with a custom shower screen for V60) is set at, in terms of the flavour profile, and whether this depends on the stage of the brew (eg during the brew not continually reheating the kettle and letting it slowly drop in temperature over the brew time).

Some context is I am coming from an EK43 to an OE Apex Manual Grinder, and I am mostly using a Melodrip but also use a bare kettle still, and I always use a V60.

Some questions / thoughts I have are:


If one can get a good even extraction, in general will a lower brew temp accentuate sweetness over acidity, AND/OR reduce bitterness and astringency?

What types of beans or roast profiles are less likely to taste good starting with boiling water? I find roasts that have been taken a bit too far (ie too dark) are really susceptible to boiling creating bitter or even ashy flavours, but that is really a roast defect...

Later in the brew, can lower temperatures as one would see by not reheating the kettle during the brew be an advantage, perhaps the hypothesis being that it reduces the chance of extracting bitter or astringent compounds late in the brew, and that diffusion into the larger particles will extract what we want without needing a higher temp?


Thanks for any thoughts...


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## MWJB (Feb 28, 2012)

1. How are we measuring extraction evenness? An even extraction, or even enough, should be tasty, uneven will probably be low and sign of a major miscalculation in grind. But anyhow, Assuming you are hitting nominal extractions, the temp must be high enough and I don't think there is much data on effect of brew temp on flavour balance, at the same serving temp (high serving temps are known to accentuate bitterness & acidity). If your brew temp is bizarrely low, then you might struggle to hit nominal extraction, without major changes to regime or grind. That was a lot of words for, "basically, we don't really know" 

2. At the moment I am brewing an espresso roast decaf bean in the mornings, darker than I would normally drip brew with, boiling bloom, stir, leave until 30s, rest of water in by 1:10, stir surface. Tastes clean & balanced, obviously some roast (nutty, toffee) but no defect/malfunction. Occasionally, I also brew up Illy (red tin & Yirg), always start with boiling water & the coffee tastes as it should. Are you sure the temp is responsible for bitter/ashy flavour? CBI suggested acceptable brew temp was "between boiling & serving temp (~80C)". If you are pouring boiling water from a kettle, it won't be anywhere near boiling once it has formed a slurry.

3. I don't think there has been any way identified to get certain compounds to queue jump order of solubilty, via slurry temp. If the water cools enough, all extraction should reduce in rate.

At the end of the day, ashy & astringent suggest more of an issue than temp. It's hard to talk about extraction & temp without any datums on either.

Low side of normal extractions can be ashy (trough between the double hump), low extraction with a coarse grind can be astringent & woody, despite there being a big margin for you to increase extraction. Dry, smokey, over-extraction is pretty rare if you are dialled in. If it's common, then you need to change something, you should be able to stay

I did some tests, just a few & not to be taken as significant data - 3x dose, bloom 45s, rest of water in quick vs small bloom 30s, 6 pulses 20s apart. (Both boiling water at bloom, no reheating because it's not feasible unless you are pulsing at particularly large intervals, like 45s, or 1:00.)

Bloom 30s with 15g, 35g every 20s, total brew time 3:20 - 89C dropping to 86C in brewer slurry. Plastic brewer.

Bloom 45s with 40g, all in fast, stir at fill, total brew time 2:56 - 90C dropping to 88C. Plastic brewer.

Bloom 45s with 40g, all in fast, stir at fill, total brew time 2:35 - 89C dropping to 85C. Ceramic brewer.

All were normal extractions, I had to guesstimate grind size for the 'all in' brews so I won't make any determination on effect on taste, but differences in temp don't seem particularly large? If you pour water in to a brewer & that same weight of water starts at the same temp & takes the same time to make the same amount of liquid in the cup, what scope is there for large changes in brew temp?


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## bpchia (Dec 23, 2014)

MWJB said:


> 1. How are we measuring extraction evenness? An even extraction, or even enough, should be tasty, uneven will probably be low and sign of a major miscalculation in grind. But anyhow, Assuming you are hitting nominal extractions, the temp must be high enough and I don't think there is much data on effect of brew temp on flavour balance, at the same serving temp (high serving temps are known to accentuate bitterness & acidity). If your brew temp is bizarrely low, the you might struggle to hit nominal extraction, without major changes to regime or grind. That was a lot of words for, "basically, we don't really know"
> 
> 2. At the moment I am brewing an espresso roast decaf bean in the mornings, darker than I would normally drip brew with, boiling bloom, stir, leave until 30s, rest of water in by 1:10, stir surface. Tastes clean & balanced, obviously some roast (nutty, toffee) but no defect/malfunction. Occasionally, I also brew up Illy (red tin & Yirg), always start with boiling water & the coffee tastes as it should. Are you sure the temp ids responsible for bitter/ashy flavour? CBI suggested acceptable brew temp was "between boiling & serving temp (~80C)". If you are pouring boiling water from a kettle, it won't be anywhere near boiling once it has formed a slurry.
> 
> ...


Thanks for the thoughts Mark, fantastic...

I think perhaps it wasn't that the darker roasts were susceptible to high temps, but rather just that they were very soluble and required coarsening of the grind...while I don't think the conclusions drawn had any evidence, the Matt Perger "experiment" here





 got me second guessing going for a coarse grind with lower levels of fines...

Few more questions Mark or anyone...:

1. I just picked up a Kruve, not really for getting rid of certain sizes (although I will probably discard boulders), but more for getting an idea of my grind size...what grind coarseness are you finding you are liking the most? Again, realise this can't be generalised too much!

2. Mark have you switched to water all in one go? Your blog and V60 video has pulsing.

3. Any recent thoughts on Melodrip? I realise there are two other threads but they're dead, and the Melodrip is somewhat related to my thread title. I've had mixed results. Can result in nice sweet clean cup, but can also relate to muddled flavour (ie not very transparent or focused for want of a better word)

4. Is your hypothesis just always go boiling and then adjust either grind size, pulsing, batch size or other to manage extraction level?

5. Really interesting point about not being able to selectively get certain flavours out with any method...and that just the more you extract, the closer you get to the brew being overly bitter or falling over the cliff of sweetness and brightness and becoming flat...are you pretty certain about this?

Thanks!


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## MWJB (Feb 28, 2012)

1. For V60 anywhere between 7% & 15% passing through the 400. At around 12% I'd bloom followed with 6 pulses. Coarser I just pour 20g every 20s, no stir, no extended bloom, fine tune tighter grind if abnormally weak.

2. No, never had a good result with single pour V60, I don't make brews as big as Scott does, I tend to stick to 12-14g per cup (don't have many large mugs). Still pulse with V60. However, with a Melita cone (same grind, same weights) the pulses are bigger & pretty much a continuous pour, so for me it varies with how the brewer itself regulates flow.

3. Don't have a Melodrip, before Melodrip a few of us used Aeropress & Aeropress caps to a similar end. My best results with this have been with Kalita Wave, with enough pulses to get a normal extraction with V60, I can get OK brews, but seem a bit silty on the tongue?

4. Yes. But I rarely adjust anything once set.

5. There was a study by MIT/CBI that brewed immersions at various temps, tannins dropped off a tad at lower temps, otherwise the other components seem to extract proportionally to EY, there was also a video knocking about on Youtube where some scientists found the same compounds in cold & hot brew.

There are multiple causes of bitterness/dryness/astringency...some may be related to over-extraction (for me this is a specific, smokey, slightly sickly, caramelley dryness, like smoke or bitter hops), others may be excess non-dissolved particles getting into the cup, or under/low-extraction. It's only over-extraction (easier at high temp & fine grind) that we can blame for extracting excess solubles.

Though, your average extraction may vary with grind size - For my bloom & 6 pulse cups, 13% @ 400 Kruve, brews, I can average 20%EY easily across origins (almost none under 18%, nor over 22%). If I go as coarse as possible to get a good cup at 20g/20s then most seem to fall between 17 & 20%, but the 17% coarse brews don't taste as bad as the 17% finer brews...possibly here the larger particles are so large the outer layers are being scrubbed of solubles before the inner layers can give up enough to bring the whole EY up.

I find the Kruve is more useful as a calibration tool with the XL set (1200, 1400, 1600), I bought a 2nd sifter so I can sift 400, 800, 1200, 1600. Otherwise I'd use 400 in the bottom & the largest (1000, or 1100) in the top.


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## Power Freak (Dec 14, 2018)

bpchia said:


> Hi all,
> 
> With the usual disclaimer that the ideal temperature for brewing depends on lots of factors including perhaps from most important to least important the roast profile, bean, brew method, agitation, etc....I'm wondering if we can discuss the effect of temperature that a pour over kettle (or automatic brewer for that matter, very keen on Scott Rao using the DE with a custom shower screen for V60) is set at, in terms of the flavour profile, and whether this depends on the stage of the brew (eg during the brew not continually reheating the kettle and letting it slowly drop in temperature over the brew time).
> 
> ...


My thoughts (none of this even vaguely scientifically studied):

1) Ignoring the "even extraction" part (I assume you mean keeping the EY the same for each brew): taking the same beans/grind/technique but pouring one cup at say 95C and one at say 85C I would expect the former to be brighter and more acidic and bright, the latter to be sweeter and flat. From experience it is not hugely sensitive to temperature though and you need to a decent swing in temp to notice a change.

2) Lighter roasts and denser african beans seem to cope and like the higher temperatures in my experience

3) Not sure you could tailor the temperature to target specific flavour molecules over others but what I will say is this might be more "forgiving" to brewing method, much like how a lever machine decreases temp and pressure through the shot. Whether the effect is significant enough to actually be perceived is a different matter (maybe you need to cool the water down quicker than would ordinarily happen to achieve this?)

I have always done what I now call the "Gardelli trick" where I place my brewista kettle on hold and pick up the kettle/base together and pour from there. With the kettle filled relatively full the temp is kept pretty stable throughout the entire pour. It feels a bit awkward at first but you get used to it. I'm not sure it actually makes a difference to my brewing but it makes me feel better about keep variables constant each time. You can see what I'm trying to explain (badly) in the video below:


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## bpchia (Dec 23, 2014)

MWJB said:


> Though, your average extraction may vary with grind size - For my bloom & 6 pulse cups, 13% @ 400 Kruve, brews, I can average 20%EY easily across origins (almost none under 18%, nor over 22%). If I go as coarse as possible to get a good cup at 20g/20s then most seem to fall between 17 & 20%, but the 17% coarse brews don't taste as bad as the 17% finer brews...possibly here the larger particles are so large the outer layers are being scrubbed of solubles before the inner layers can give up enough to bring the whole EY up.
> 
> I find the Kruve is more useful as a calibration tool with the XL set (1200, 1400, 1600), I bought a 2nd sifter so I can sift 400, 800, 1200, 1600. Otherwise I'd use 400 in the bottom & the largest (1000, or 1100) in the top.


Great info to ponder...


are most of your brews around this 13% of grounds discarded from the Kruve 400?

What do you mean my 20g/20s?

Do you prefer more 20% EY cups or 22% EY cups?

I'm trying to hit 23% without bitterness or flatness...some coffees I can, some I can't...I guess trying to get as much EY as possible until you get the bitterness or flatness or astringency and then pulling back a fraction is usually best...

When I say "assuming even extraction", I mean that if you have channeling, don't agitate the grounds evenly via pour technique, don't wet all the grounds at the same time, then that's a separate problem...I'm assuming none of this is occurring (even though with a manual method it is occurring for sure!!)


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## bpchia (Dec 23, 2014)

Power Freak said:


> I have always done what I now call the "Gardelli trick" where I place my brewista kettle on hold and pick up the kettle/base together and pour from there.


I've seen Devin Loong do this in Brewers Cup as well...I find with the Brewista that it's annoying if you set it at 100C, then it tries to edge its way to 100C like it would when setting it at say 98C, rather than it knowing that you can't get above 100C for water so just get there ASAP!


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## MWJB (Feb 28, 2012)

bpchia said:


> Great info to ponder...
> 
> 
> are most of your brews around this 13% of grounds discarded from the Kruve 400?
> ...


1. I use the Kruve to calibrate grind setting, I don't discard any portion of a typical dose that I brew drip with (I do discard sub 400 for immersion brews when I feel like a very clean one). If I was to discard a portion of a drip dose it would be the largest 10-20%, not the smallest.

2. With a coarse grind pour 20g of brew water every 20s for a 1mug brew (200-240g).

3. You can't pin EY down that precisely over a range of origins, for the medium grind 20%avg cups, some taste great at 18%, some at 22%, sometimes a tad higher. The coarser brewed cups can be brighter, cleaner, maybe not as sweet.

4. See 3, I don't know why you are trying to hit 23% with drip brews, a few coffees might be good here but you're way over what will be a sensible average.

5. Too much assuming  If the extraction is of a normal level and it tastes good, how uneven can it be?


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## bpchia (Dec 23, 2014)

MWJB said:


> 1. I use the Kruve to calibrate grind setting, I don't discard any portion of a typical dose that I brew drip with (I do discard sub 400 for immersion brews when I feel like a very clean one). If I was to discard a portion of a drip dose it would be the largest 10-20%, not the smallest.
> 
> 2. With a coarse grind pour 20g of brew water every 20s for a 1mug brew (200-240g).
> 
> ...


All sage advice! How do you find your immersions vs drip? Are you filtering the immersion with a V60 to clean it up at the end?


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## MWJB (Feb 28, 2012)

bpchia said:


> All sage advice! How do you find your immersions vs drip? Are you filtering the immersion with a V60 to clean it up at the end?


I find generally have a lower preference for immersions and most of the time I'm not inclined to wait that long for them, a weekend morning thing/French press for big gathering for me. I don't mean immersions aren't as tasty, but I don't find them as repeatable & if something goes wrong, you've wasted considerably more time than if you were drip brewing (which rarely goes badly wrong, if it is less forgiving of roast issues).

I don't paper filter Bodum French press/Sowden brews, I pour very carefully & pour off the surface layer (this is where a significant amount of silt sits, it's not all at the bottom of the pot). If the silt is more than a light dusting in the last sip, or two, then that's down to something I have done wrong when decanting. Always a bit hazier than paper filtered drip, but I don't like them chewy. Filtering always seems to cause shift in flavour & can add 10mins to FP brews.

I certainly sift out sub 400/500 if I'm using my Espro press, still pour off the surface layer, but sifting allows you to be a bit more carefree & the Espro needs to be plunged so you can't use the Hoffmann method. I sometimes also sift Clever brews, but at the finer grinds I use this can be 20%+ of the ground dose.

I do paper filter Turkish brews, I use a Chemex paper (seems the most transparent if secondary filtering/polishing) in a V60 and pour around the top of the filter paper & hold back as much of the grounds as I can in the cezve.


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## the_partisan (Feb 29, 2016)

For drip, I hardly find coffees taste good much higher than a roughly 20% EY avg - you might get the odd Kenyan or Ethiopian which will extract to 22-23% but others might get too unbalanced. I've had plenty which were really exceptional around 18% (typically Bourbons or Pacamara). So in general, the sweet spot seems to lie between 18-20%. As for the grind, I prefer the coarsest grind possible which will give me the most clarity and balanced tasting notes. You don't need to grind as fine as possible unless you're trying to save on coffee and brew with maximum efficiency. I don't see people complaining they "only" got 40g of beverage from 18g of beans when making espresso.

So it's better to dial in based on flavour and then keep notes of keeping track of your EYs for consistency.


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## bpchia (Dec 23, 2014)

MWJB said:


> I do paper filter Turkish brews, I use a Chemex paper (seems the most transparent if secondary filtering/polishing) in a V60 and pour around the top of the filter paper & hold back as much of the grounds as I can in the cezve.


I'm really keen to try out this method, but currently I don't have a grinder that will go fine enough...I was inspired to do it by this:





[/QUOTE]

Great advice...I'm going to recommence using my log book of all my brews (grind setting, dose, water wt, water temp, bev wt, TDS, EY, comments eg method variations)


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## MWJB (Feb 28, 2012)

bpchia said:


> I'm really keen to try out this method, but currently I don't have a grinder that will go fine enough...I was inspired to do it by this:


You don't need to go super fine to get a good extraction, the very fine grinds help with forming foam, but you can also use the fine end of drip/coarse espresso (26% immersion, before filtering, is not hard to hit), especially if you are going to filter with paper, as you'll lose the foam anyway.

I don't think you need to be quite as hands on as Jeremy in the video, you don't need a temp probe, just kill the brew when it foams. I start with pre boiled water in the cezve, add grinds & combine, then slow heat up on a low electric hob (maybe start with cold water for a gas hob, or aggressive induction etc.). Remove when foamed, skim the surface & filter through a rinsed paper, don't pour all the slurry into the filter. You don't need to kill the filtration after a minute either, if you do, you'll just lose more beverage. I don't like the Hario papers for filtering, seem to increase dryness compared to unfiltered brew (love them for brewing though).

I call a recipe that only works with certain origins/processes, "a happy accident", or "Russian roulette".  A recipe is expected to still work when you change origin or process, we're not talking espresso here, we have a bit more latitude with brewed.

As with French press, the biggest pitfall with the polished cezve/WendelHoff is pushing too much silt through the paper (again a slightly coarser grind than typical Turkish helps here too).


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## Power Freak (Dec 14, 2018)

the_partisan said:


> For drip, I hardly find coffees taste good much higher than a roughly 20% EY avg - you might get the odd Kenyan or Ethiopian which will extract to 22-23% but others might get too unbalanced. I've had plenty which were really exceptional around 18% (typically Bourbons or Pacamara). So in general, the sweet spot seems to lie between 18-20%. As for the grind, I prefer the coarsest grind possible which will give me the most clarity and balanced tasting notes. You don't need to grind as fine as possible unless you're trying to save on coffee and brew with maximum efficiency. I don't see people complaining they "only" got 40g of beverage from 18g of beans when making espresso.
> 
> So it's better to dial in based on flavour and then keep notes of keeping track of your EYs for consistency.


I agree with this. In fact I stopped measuring EY altogether, I found it too distracting and I was getting too caught up in getting to specific numbers I thought would give the best taste, instead of actually tasting the coffee and judging that way. I was falling victim to Goodhart's law: "When a measure becomes a target it ceases to become a good measure" (Not sure he was talking about EY of coffee however)

For pour-over I tend to find I like the coarser end of the grind settings for exactly the reasons described here.

The saving on coffee is an important point, at home you likely don't go through the volume of coffee where "efficient extraction" makes financial sense. For a cafe being able to use even 0.5g of coffee less per cup adds up to rather large savings.


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## MWJB (Feb 28, 2012)

Power Freak said:


> The saving on coffee is an important point, at home you likely don't go through the volume of coffee where "efficient extraction" makes financial sense. For a cafe being able to use even 0.5g of coffee less per cup adds up to rather large savings.


Inneficient extraction might be avg 16%, even for the home user that's the difference between 13.5g of coffee per mug @ 1.35%TDS (just an example of a reasonable average not a magic target) & 17g, or, another 4 servings from a 250g bag.

0.5g per dose will get lost in the noise of dose variance.

There is no need to shoot for specific numbers, you will waste more coffee & enjoy the coffee you do make less. A reasonable range is all you need, measure a few to make sure your method is consistent & then get on with it.


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## the_partisan (Feb 29, 2016)

MWJB said:


> Inneficient extraction might be avg 16%, even for the home user that's the difference between 13.5g of coffee per mug @ 1.35%TDS (just an example of a reasonable average not a magic target) & 17g, or, another 4 servings from a 250g bag.
> 
> 0.5g per dose will get lost in the noise of dose variance.
> 
> There is no need to shoot for specific numbers, you will waste more coffee & enjoy the coffee you do make less. A reasonable range is all you need, measure a few to make sure your method is consistent & then get on with it.


Plenty seem to be using such ratios (+70g/L) in brewing competitions, I think it probably highlights some characteristic of the coffee and can taste quite intense. I think this year's winner used something like 17g to 220g. I've seen much higher ratios in Aeropress competitions too even up to 1:10 I think.

Besides Scott Rao & Matt Perger I don't really see any other roaster pushing or talking about very high EY - for some reason both of them are very outspoken about this and talk about nothing but maximizing EY or boasting about how high EY they get with their latest gadgets. For example the best known roaster here in Denmark - Coffee Collective brew their Kalitas at 16g/250g and aim for ~%1.35-%1.4 TDS which will give them EY between 18-19% (proof:


__
http://instagr.am/p/BpTwEM2ntnN/
).

So as long as coffee tastes good & balanced, don't worry about the numbers too much.


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## MWJB (Feb 28, 2012)

the_partisan said:


> Plenty seem to be using such ratios (+70g/L) in brewing competitions, I think it probably highlights some characteristic of the coffee and can taste quite intense. I think this year's winner used something like 17g to 220g. I've seen much higher ratios in Aeropress competitions too even up to 1:10 I think.
> 
> Besides Scott Rao & Matt Perger I don't really see any other roaster pushing or talking about very high EY - for some reason both of them are very outspoken about this and talk about nothing but maximizing EY or boasting about how high EY they get with their latest gadgets. For example the best known roaster here in Denmark - Coffee Collective brew their Kalitas at 16g/250g and aim for ~%1.35-%1.4 TDS which will give them EY between 18-19% (proof:
> 
> ...


Sure but the bigger doses in immersion brews are to bolster strength/intensity, an immersion at 20% is weaker than a drip brew at of the same ratio. Same for very subtle coffees brewed as drip like some Geshas.

What I'd like to see from Rao & Perger are realistic ranges of EY, over a range of origins, rather than suggesting, say 23%, is an ideal target. I don't really see either suggesting targets for brewed outside the normal range though.

18-19%EY for drip is normal range, not high, not low - under-extraction (under 18%) is more likely than over for those who don't measure. So, yes, don't worry about the numbers once dialled in (the same inputs repeated will yield the same output, within the scope of normal variation - you establish consistency at the point you pour the last drop of water, long before you measure anything). But if you find yourself constantly adjusting & dialling in, your recipe is probably not repeatable, or is targeting an unrealistic range. Here, measuring can be a handy sanity check.


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## the_partisan (Feb 29, 2016)

I meant that targeting 18-19% will give you fewer bad cups than always targeting 21-23%. When I first got my EK43 I had a recipe where I was grinding very fine and usually ending up between 21-23%, I quickly found it while it can give you some very good cups, it was hit and miss a lot of the time. Dialling back to aim for 18-20% seems to work much better for me, very few off cups and coffees which have tasted good at 23% also tend to taste pretty good at 18-20%. Tasting notes don't particularly change.


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## bpchia (Dec 23, 2014)

the_partisan said:


> Besides Scott Rao & Matt Perger I don't really see any other roaster pushing or talking about very high EY - for some reason both of them are very outspoken about this and talk about nothing but maximizing EY or boasting about how high EY they get with their latest gadgets.


I think my original post and me saying I was shooting for 23% was exactly because of these guys...I do respect them and most of their views are helpful to me, but it also can lead me astray and as @MWJB has noted, wasted coffee and time.

Good to get a balancing view, thank you all.


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## bpchia (Dec 23, 2014)

I know this is a very broad question, but what kettle temp range are people using for V60s? Did this change with the Aeropress shower screen method, trying to extrapolate to the Melodrip...?


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## MWJB (Feb 28, 2012)

I bloom as soon as the kettle clicks off boil.


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## the_partisan (Feb 29, 2016)

I also use boiling water and don't preheat the V60 or rinse filters. If you're using non-plastic V60 it might make sense to pre-heat it with boiling water though. I tried rinsing for a while but I didn't find it to make any difference taste wise, if anything they seem to make the filters less porous sometimes?


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