Grind Retention: Overview and Comparison
Articles Blog

Grind Retention: Overview and Comparison

December 31, 2019

grind retention is a phrase we use often
when discussing the merits of different grinders if you’re not familiar the
concept is simple as beans are ground there are areas within the burr chamber
where grounds can rest without being expelled into your portafilter in this
video i’ll be discussing the effects of grinder tension how to manage them and
comparing eight different grinders in our lineup in many grinders this is an intentional
design element that helps reduce static and maintain flow for consistent dosing
while there are benefits they’re also drawbacks to grinder tension grounds
retained in the burr chamber will lose freshness this is an added variable for
home briefs those who aren’t using the grinder as much as a cafe this retention
also means that an adjustment and grind size doesn’t have immediate effect with
some particles from the previous grind setting making their way into your dose
both of these issues can be solved by a quick purge before your first shot of
the day for those that wish to single-dose their beans some grinders
can work exceptionally well however grinder tension in certain models can
make them challenging so what does this mean for you whether you fill your
hopper and use time dosing or single-dose your beans incorporating a
purge into your teen is invaluable if you make just a couple drinks one
morning the next day it’s a good idea to purge a few grams of coffee generally
just a second or so i’ve grinding with a full hopper this will flush out the
stale grounds from yesterday if you don’t these still grounds will
cause your first shot of the day to be what is scientifically referred to as a
gusher the flow through the grounds will be far too quick and your shot will be
watery generally if the gap between shots is around 12 hours or less the
effect is negligible the greater a grinders retention the
greater the impact so we recommend purging a bit more coffee the more
attention your grinder has a grinder with minimal retention will help you
marginally reduce waste by reducing the need for a purge if you aimed a single
dose when a grinders retention is likely among the greatest determining factors
and whether or not it will suit your needs there’s an added factor to
consider beyond purging the more retention a grinder has the more
variation in output you’ll see generally these variations peak at about one gram
and the best remedy is to stick to a consistent routine in order to ensure
consistent output let’s compare the retention of a few
different grinders many tests we’ve seen start with a completely clean grinder
and mentioned the amount of coffee retained after a single dose this
doesn’t represent the amount of grounds that build up in normal use and paints
an unrealistically favorable picture our goal with measuring attention is to
quantify the amount of loose grounds that rest in a grinder in normal use
whether using time dosing or single dosing these grounds are what will
impact your shots and therefore influence your routine we around 80
grams of coffee through each grinder until no more coffee was dispensed we
then open the burr chamber and swept out all the loose grounds including in the
chute and behind the screen we collected those grounds and then weighed them this
measurement is what we counted as the grinders total retention we’ll start with the baratza sette 270 and mignon specialita to small burrs make 4 small retention the sette 270 with its
small conical burrs has almost zero space to collect grounds thanks to its
innovative shape its unique burr assembly an incredibly short vertical chute work
wonders with retention of less than a gram altogether this makes it one of the
most effective single dosing grinders on the market the Eureka Mignon Specialita is a great example of a low retention flat burr grinder it’s 55
millimeter burrs are on the smaller end of the spectrum and it’s impressively
compact bird chamber it leaves little room for buildup with only about one
point three grams of retention this works wonder it’s one single dosing a
rare honor for a flapper grinder now let’s look at the Eureka atom t-64 and
zenith this price range contains the bulk of prosumer flat burr grinders most
of these grinders have relatively large burrs and motors they’re built to
produce very consistent grounds quickly these larger bird chambers inevitably
make for greater retention but some designs mitigate that better than others
the Eureka atom for instance has mid-sized 60 millimeter burrs with a
very small gap between the burrs and the inner wall burr chamber
this combined with Eureka’s proprietary forked screen which causes very little
retention means that despite being quite a bit larger than the first few grinders
we looked at it only retains around 2 grams though the atom does have low
retention we don’t recommend it for single dosing it’s designed with the
weight of a full hopper of beans in mind and some pieces like the auger make it
far faster with a full hopper but are counterproductive when single dosing the
t-64 has 64 millimeters burs but its chamber is also tight-fitting meaning
there’s only a small gap for coffee to collect it’s 4 point 5 gram attention is
a big jump from the smaller grinders we mentioned before but let’s compare it to
something of its own caliber Eureka Zenith it has 65 millimeter birds just
slightly larger than the t-64 but more importantly you can see that the gap
surrounding the burrs is considerably larger this key difference is what
generates its 6 point 5 gram retention in practice this difference is nominal
and entirely manageable with the same purge now let’s compare the Olympus the V-Titan and the KRE this price range contains grinders that are built to
handle commercial use and are often built with top-notch materials and
plenty of attention to detail having blazing speed and impressive
consistency means that these grinders are not designed with single dosing in
mind and therefore have a good bit of retention let’s start with the Eureka
Olympus it has huge 75 millimeter flat steel burrs
but it’s bird chamber has a smallest gap between the inner walls and the birds
themselves additionally Eureka’s unique screen design and the immense torque of
the Olympus motor made for a surprisingly low retention of 3.5 grams
the bird chamber of the V Titan is also designed to hug tightly around its large
64 millimetre birds and has four paddles where most grinders have two or three
this design leaves relatively little space for the grinds so the V Titan only
has about 4.5 grams of attention the eureka kre is unique in that it is one
of a select few large conical burr grinders in our lineup well it’s one of
our favorite grinders with hopper full it retains 12 grams of coffee making it
less than ideal for single dosing large conical burrs like these require the
aforementioned purge but they also benefit greatly from a more consistent
routine by ensuring that you grind for approximately the same time and use the
same technique with each dose you can ensure that you get an output within
about one gram of your input All in all
under tension matters to you depends on your preferred routine and how many
drinks are making in a day for those that wish to single-dose choosing a
grinder often involves balancing the benefits of larger Brewers and motors
with their requisite increase in retention for those that use time dosing
it’s simply a matter of understanding the amount of retention and knowing how
much to purge to ensure consistently delicious results we’ve used every
grinder we sell extensively so if you ever have a grinder attention questions
regarding a specific grinder feel free to leave a comment below or give us a
call we’re happy to provide insight if you feel like you’ve got a better
understanding of grinder tension after this video be sure to hit the like
button below and if you want to keep up with our overview and educational videos
be sure to hit subscribe

Only registered users can comment.

  1. Sorry for the lengthy comment but this video couldn’t have come at a better timing as I’m currently looking into buying a low-retention grinder.

    Everyone keeps talking about low/zero retention and single dosing. This video is simply the only source of true information on grind retention. Thank you so much for making this super informative video.

    Purging before every grind is a non-issue in my opinion. I usually make 2 shots in a row so will only need to purge once a day, which will cost me a little more than one full espresso per bag — around $1 per 250g/9 ounces of coffee I consume per week. If I consume 52 bags a year, then that’s a $50 extra per year that I’m willing to pay for my comfort and time saved.

    For those really worried about grind retention, you should get titan hand grinders like HG-1, Kinu M68 and Helor Stance. Requires around 20-25 seconds of work and single dosing the beans each time.

    I currently own a Kinu M47 which I use daily to grind my espresso and I pull great shots, although the grinding process has gotten tiring as it takes me 45-55 seconds to grind for espresso. A 1 second purge and 5 second grind sounds about perfect.

    I’ll make my final decision on upgrading to an M68 or getting an Olympus / 65E Speciality at the end of the month.

  2. Can one definitively say that the retained grinds which are stranded in a position in the grinding chamber are necessarily evacuated with a purge, or does some portion of the stranded grinds remain stranded to age further?

  3. You guys are great – very informative video. I learned I may be over-purging my Mazzer Mini E, used for home use. Every morning I purge for 5 – 7 seconds (I use the hopper to store a couple day's worth of beans, and do not single dose). Sounds like too much. I also purge if it has been an hour or so since the last grind session. That may not necessary.

  4. I see that you guys are using grooming tools at 1:23. May I ask A) if you had to choose one, would you choose a leveler or a tamper and B) which model(s) you guys prefer? As a newbie home barista, I suspect that these tools might help me produce more consistent results.

  5. Worth looking at the Niche Zero grinder, just released. Is a single dosing grinder, but with virtually no retention. I have ordered one as the build quality seems particularly good.

  6. Good video. Very well presented. As a home barista, I completely agree with the purge & consistent process concepts. They do help. Additionally, I find that using a small vacuum at the inlet & output side of the grinder daily use helps to remove residue. I use a small, hand held battery powered Dyson. It helps remove at least the loose residual grinds. The vacuum is also very useful in cleaning up my work area.

  7. May I ask how many times di you repeat the measurement for each grinder? Also, when single dosing on a Zenith 65 E how much coffe would you use to flush the grinder before the first coffee in the morning? Anything above 6.5g?

  8. I was thinking about ordering a KRE to substitute my Ceado E37S (2nd gen) as I prefer a conical. I saw the KRE has the Blow Up system. Do you sell the blow up hopper and have you tried if it really improves on retention like Eureka claims?
    Thank you for a great video!

  9. Is sette 270 good enough for home barista and single dosing with much expensive grinder like Ek43 or mythos 2?? Sorry for this silly comparison question 😅

  10. I got the new Ceado E37S for home. I only drink 1-2 coffees a day… meaning, before I grind my coffee would be advisable to always purge a portion to avoid retention for my portion? Thanks

  11. Thanks for this! so if money were no issue; which eureka grinder would you choose; that has best balance between quality/coffee taste/consistency and retention?

  12. Hello, I have a T-64 I purchased from you. here is my question. You state that grind retention is 4.5 g. how much of that 4.5 grams is replaced with new coffee being ground vs coffee simply taking up some space and being relatively fixed in place. ( if I put 20 g in and grand 20 grams out is 4.5 g of what I get out old coffee an 15.5 g new grind?

Leave a Reply

Your email address will not be published. Required fields are marked *