Solubility

[gooseneck]

I'm wondering what you all use to know if you are getting good inner bean development and the right amount of solubility. Obviously taste plays a huge part in that, but haven't come across anyone saying they use a refractometer on here yet. I'd like to have one, but it's at least $270, and upwards of $750. A local coffee shop uses one, so maybe I can some how use theirs occasionally. Thoughts?

[Jayel]

I'm very glad you posted this because I have no idea about refractometers but I know many roasters use them to gauge proper extraction and such. I have one on my Amazon wish list that is only about $30 but I haven't really looked into it that much yet because I really don't know what I am looking for. I basically use my Amazon wish list as a bookmark for products I am interested in, whether I plan on buying it on Amazon or not. If you search for "refractometer" on Amazon, only three products are found (at least when I do it), and they are all roughly between $25 and $40. So I guess what I'd like to know is, what am I looking for exactly in a refractometer?

Here is the one I was looking at: http://www.amazon.com/Refractometer-Automatic-Temperature-Compensation-0-32/dp/B003H7ILCW/ref=sr_1_sc_1?ie=UTF8&qid=1456088305&sr=8-1-spell&keywords=refractomerter

[jyalpert]

I think that's a beer/wine homebrewing refractometer.  No idea if it has the sensitivity or scale necessary for coffee.

Usually coffee people talk about the VST refractometer.  Not sure if there is a cheaper version somewhere.

I personally don't really care enough to buy a refractometer, though I am a shitty barista and it would probably help me brew better.

[gooseneck]

I'm very glad you posted this because I have no idea about refractometers but I know many roasters use them to gauge proper extraction and such. I have one on my Amazon wish list that is only about $30 but I haven't really looked into it that much yet because I really don't know what I am looking for. I basically use my Amazon wish list as a bookmark for products I am interested in, whether I plan on buying it on Amazon or not. If you search for "refractometer" on Amazon, only three products are found (at least when I do it), and they are all roughly between $25 and $40. So I guess what I'd like to know is, what am I looking for exactly in a refractometer?

Here is the one I was looking at: http://www.amazon.com/Refractometer-Automatic-Temperature-Compensation-0-32/dp/B003H7ILCW/ref=sr_1_sc_1?ie=UTF8&qid=1456088305&sr=8-1-spell&keywords=refractomerter

You need one that specifically tests TDS (Total Dissolved Solids). This will allow you to use some software to calculate extraction of your beans. You want to aim for 19-22% extraction. If you're under, then that could be an indication that your beans are underdeveloped. This is mostly what I've read in Scott Rao's roasting book. In any case, here's the one I'm looking at getting (I do the same thing with Amazon Wish Lists )

http://amzn.com/B00LTH2PUG

The VST is ideal, but very expensive. This one seems to be made for coffee specifically but is more affordable.

[SusanJoM]

Aren't there a lot of factors between the roast and the cup that impact the resulting TDS? 

[gooseneck]

Aren't there a lot of factors between the roast and the cup that impact the resulting TDS?

Yes, tons. Grind type, grind consistency, water temp, coffee/water ratio, brew time to name a few. But if you can pick certain benchmarks for all of those, take three different roasts of the same bean, for example, and cup them all with the exact same parameters, then measuring TDS could help you figure out inner bean development (in theory of course). For example, if extraction in two of those three were around 20-21% and the third was around 19%, clearly then the third would not have as good inner bean development. I would suspect (again, in theory) that that cup would taste a bit more grassy, for example.

These are the types of things I've read and heard from some well respected coffee professionals (Scott Rao, Tim Wendelboe to name a few). Scott Rao says in his book that the refractometer is the single best device that has helped in figuring out extraction and as a result good inner bean development. Again, obviously taste is king, but there is a science behind why good coffee tastes so good.

Thoughts?

[SusanJoM]

I think the Tonino would be a better investment.

[Johnny4lsu]

I think the Tonino would be a better investment.

Curious why you think so? Wouldn't a coffee with darker outer development with light underdeveloped internal color balance out as a medium color?

I've never used the VST refractometers but from what I've heard they are impressive in how they help determine solubility.

I know very little about how either work so take that fwiw.

[SusanJoM]

I think the Tonino would be a better investment.

Wouldn't a coffee with darker outer development with light underdeveloped internal color balance out as a medium color?

I don't think so, but this conversation at H-B from a while back might (or might not) answer your question:

http://www.home-barista.com/home-roasting/tonino-revisited-t37769-10.html?hilit=tonino#p447869

[Johnny4lsu]

Thanks. Will check it out in a few minutes

[Crzyworm623]

I purchased a Pal coffee refractormeter a few moths back.  Sells for just under 300$. A refractormeter is an invaluable tool for brewing consistant coffee and really understanding extraction. There is no question that measuring my extraction has helped me brew better consistant coffee.

 Sometimes we all brew a great cup,  and other times a not so great cup.   There are so many variables that play a part in that. Maybe your brew method is right on, but your beans are bad. Maybe the other way around.  Either way, after calculating extraction and recording my data and brew times etc, I'm able to dial in a brew method for each bean, because it changes bean to bean. No more trying to guess why this cup was great.  If it's sour and I'm under extracted I can change one variable. Maybe grind size or add brew time and see a quantifiable number associated with that change.

My first week owning it,  I ran numerous tests changing only one variable at a time  and seeing the effect it had. Small grind adjustment is enough to change the final cup. A 7days

I can also reverse brew. Determine before hand where I want my extraction to fall based on my taste preference. Figure out what I want to aim for and based on past brew data and the vst software can usually hit my mark.  This also can maximize your profits if your In retail by using the least amount of beans while still achieving desired strength and balance. 

So onto the pal vs vst. If I had to buy again I'd buy the vst. The vst is a scientific instrument. The pal is a coffee tool. The accuracy of the pal is said to be .15%,  that is huge. That  can be the difference from a nice 20% extraction to a 23-24%extraction,  that is now bitter and should be poured out.

I find all my readings to be fairly consistant between samples,  I just can't help but think the results may not be accurate and find myself taking multiple readings to verify.  I do get the occasional reading way out of whack. But again a  tds reading of 1.3 to 1.4 is huge on the extraction calculations. As little as 10g of water can change the extraction calculation.

If you do plan on getting a refractormeter make sure you have an accurate scale,  the acaia pearl is amazing and can't suggest one of those enough.

The pal is useful and fully capable of giving you an idea of how your brews are turning out.  But if you want definitive accuracy the vst is worth saving for.   Check out Socratic coffee, they did a three part write up comparing the two and ultimately swayed me for the pal.   

[gooseneck]

Thanks Crzyworm623. Very helpful to hear this feedback. The more I looked into it, the more I realized the refractometer is most useful for extraction, which relates a ton to brewing and all the variables that go into that. I was looking at the Pal since it's less than twice the VST. I'll keep my eye on eBay for a used or older VST. Thanks agian.

[Crzyworm623]

Thanks Crzyworm623. Very helpful to hear this feedback. The more I looked into it, the more I realized the refractometer is most useful for extraction, which relates a ton to brewing and all the variables that go into that. I was looking at the Pal since it's less than twice the VST. I'll keep my eye on eBay for a used or older VST. Thanks agian.

I hope I answered some of your questions.  I typed that on my phone while on the train, so my thoughts were all over.   Here are the links to a very good comparison.  Probably the only full in depth review of the PAL too.  At the end of the day the PAL seems to be accurate enough to use, and for the price I say worth it, if that is what in the budget.  I could swallow 300$ but 800$ I'd have a hard time justifying unless I owned a shop. (got mine off ebay, went with the BX/TDS model but now I wish I just got the TDS, really no reason to see the BX and I have to hold a button to get the TDS) I use it every time I get a new coffee, at least for the first time using the brew method.  If we're going to have the freshest best roasted coffee.  We better have the freshest best brewed coffee to go along with it.   (you'll need syringe filters if using it to measure espresso or french press)

Part I

Part II

Part III


Here's an example of my first brew using my first roasted batch of coffee.  Besides it tasting great, I can see I got a great extraction.

I record all the data in an excel work sheet. Then using VST Coffee Tools for android, running in an emulator on my computer enter the numbers to get the chart and extraction numbers. (The software interface is terrible, and the windows version purchased separately is $150.00.  The android version at $30.00 is also extremely over priced.

[hankua]

I bought a Misco Palm Abbe PA202 like new off EBay, the identical meter VST uses; (sort of). Misco sells custom software programs for their meters, and VST bench tests the ones they sell to verify the accuracy/sensitivity. So the VST meter is a customized product.

My meter has the capability of reading nD which is better than Brix. VST meter might also read one more decimal place than mine in nD as well. VST has a very cool app, but deleated the nD function years ago and only reads tds. Problem is you have to be a math wizzard to understand how to program the conversions from nD to TDS. The nD/brix conversions online are really ballpark throw the dart kind of calculations. There is no way to directly plug in the reading from my meter into the current software unless someone owned the older version of the app.

The whole VST thing is complicated, controversial, argumentative, abrasive, caustic, on and on......

When they first started there were meters priced at the level a hobbyist would consider or purchase. VST decided to take a different path with the business model and go full on professional level/pricing.