Yeast Cell Density Meter

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WoodlandBrew

WoodlandBrew

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Do you want a tool that can measure the amount of yeast in your starter or wort, and is easy to use?

A product development team that I'm excited to be part of has started design of a beer color and cell density meter.

What would you expect in such a device? How about easier to use than a refractometer? More accuracy than a microscope and hemocytometer? Perhaps 5%, 1% or better accuracy? What if we added some other functions? How about being able to measure beer color using standards such as SRM and EBC? Or some of the less standard methods such as three color equivalent RGB? Lab equipment with this capability can be over $1000 and doesn't have all these features.

Would you pay $100 or $200 for a device that measures cell density more accurately than a microscope and hemocytomter, and color to SRM and EBC standards?

Our team is composed of engineers and scientists with over 40 years of combined in field professional experience. We are looking forward to building a product designed for you, the brewer, but we need your feedback.
 
I think this would be a useful tool to have. I couldn't care less about measuring color but cell density would be nice. I think having an accuracy to within 5% would be sufficient and I probably wouldn't pay more than $100 for such a tool. There are plenty of estimation calculators out there that get close enough and they are free.
 
To measure cell density and color, yeah, I'd definitely be willing to pay $100. Not sure I'd be interested at $200. I suppose I'd be willing to pay an extra $20 for a meter that measures both cell density and color vs. one that only measures cell density.

Good luck with the project. It sounds exciting.
 
I think that could become a key tool for monitoring pitching rates and sounds much more approachable (and faster) than a microscope and hemocytometer. I would focus on that vs the SRM measuring or maybe offer SRM as an upgrade. I would probably pay between $100 and $200 depending on its accuracy vs the micro/hemo counting. Good luck!
 
Thanks for the feedback so far! I'm confident that we can make a product that fits the expectations that you guys have laid out here. Based on our calculations it looks like the devices will be faster and more accurate than a microscope. Accuracy of better than 5% should be achievable.

With existing cell density meters the result needs to be scaled for the volume of the starter. Would it be valuable to have that built into this meter by selecting the volume of your starter? The actual number of cells could be displayed instead of just a density.
 
WoodlandBrew said:
Thanks for the feedback so far! I'm confident that we can make a product that fits the expectations that you guys have laid out here. Based on our calculations it looks like the devices will be faster and more accurate than a microscope. Accuracy of better than 5% should be achievable.

With existing cell density meters the result needs to be scaled for the volume of the starter. Would it be valuable to have that built into this meter by selecting the volume of your starter? The actual number of cells could be displayed instead of just a density.
Click to expand...

Probably it would it be convenient, but remember, the people interested in this are already doing a lot of math. A mere X cells per ml type of scale could easily be enough for what most of us will want.

I guess what I'm saying is, yes, that would be blingy, but I wouldn't want to pay more for the product because it has it.
 
jbaysurfer said:
probably it would it be convenient, but remember, the people interested in this are already doing a lot of math. A mere x cells per ml type of scale could easily be enough for what most of us will want.

I guess what i'm saying is, yes, that would be blingy, but i wouldn't want to pay more for the product because it has it.
Click to expand...

+1
 
I'm in agreement with the general consensus. More interested in cell density than color, don't need a cell count based on volume per se but would take it as a free feature (otherwise, the math is simple enough), and the <$100 ballpark is where I would be willing to get a toy like this.
 
jbaysurfer said:
Probably it would it be convenient, but remember, the people interested in this are already doing a lot of math.
Click to expand...
Good point. I'll see what we can do to add this without increasing cost.

Thanks everyone for the feedback. Knowing people are interested is good motivation!
 
WoodlandBrew said:
Thanks for the feedback so far! I'm confident that we can make a product that fits the expectations that you guys have laid out here. Based on our calculations it looks like the devices will be faster and more accurate than a microscope. Accuracy of better than 5% should be achievable.

With existing cell density meters the result needs to be scaled for the volume of the starter. Would it be valuable to have that built into this meter by selecting the volume of your starter? The actual number of cells could be displayed instead of just a density.
Click to expand...

What does the volume of your starter have to do with it though? That assumes you know the starting count to begin with. Im going to assume by starter you mean the actual yeast slurry produced by the starter.

What you need to know is the volume of your yeast slurry, take measured sample of that out, get the count, then do the math to figure how much yeast is in your entire slurry.
 
FuzzeWuzze said:
What you need to know is the volume of your yeast slurry, take measured sample of that out, get the count, then do the math to figure how much yeast is in your entire slurry.
Click to expand...

Yes exactly, except you don't even need to measure the volume of the sample you take from the slurry or starter! Also, we might have the device do the math for you. So you would fill a small vial, put it in the machine, select that it is from a 2 litter starter (for example) and it would tell you how many cells you have (for example 220 billion)
 
WoodlandBrew said:
Yes exactly, except you don't even need to measure the volume of the sample you take from the slurry or starter! Also, we might have the device do the math for you. So you would fill a small vial, put it in the machine, select that it is from a 2 litter starter (for example) and it would tell you how many cells you have (for example 220 billion)
Click to expand...

I guess thats my point, what does it coming from a 2L starter have to do with anything? You dont know if its a 1.005 2L starter or a 1.080 2L starter...granted everyone aims for 1.035-1.040 but sometimes not always exact.

The starter volume doesnt tell you anything does it? If your package is at 10% viability and you put it in a 2L starter your result is much different than one thats 99% viability...

I'd think you would need a measured amount, even if its non specific, like 3 drops from a dropper, that go into the device to measure it, or else how do you know how much yeast is in a given amount of the slurry?
 
FuzzeWuzze said:
You dont know if its a 1.005 2L starter or a 1.080 2L starter...granted everyone aims for 1.035-1.040 but sometimes not always exact.

... If your package is at 10% viability and you put it in a 2L starter your result is much different than one thats 99% viability...
Click to expand...
Yes, you have that right. There are a number of factors that play into the final cell count of a starter.
I'd think you would need a measured amount, even if its non specific, like 3 drops from a dropper, that go into the device to measure it, or else how do you know how much yeast is in a given amount of the slurry?
Click to expand...
I can see how you might think that, but actually you don't need to know the volume of the sample because the meter measures cell density directly and is independent of the volume. (The way it works is similar to ones used in labs like this Biowave Personal Cell Density Meter although the price point we are looking at is much much lower.) As long as the vial is more that half full the meter can make a reading.

Cell density is typically expressed as Billions of Cell per Liter. Cell Density multiplied by volume gives you the number of cells in that volume. So if the device measured 110 Billion Cells per Liter and the sample was taken from a 2 Liter starter then you would know that your starter produced 220 Billion cells.

So the question is would you like to only know cell density, or would you like to the device to determine the total cell count as well?
 
WoodlandBrew said:
Yes, you have that right. There are a number of factors that play into the final cell count of a starter.
I can see how you might think that, but actually you don't need to know the volume of the sample because the meter measures cell density directly and is independent of the volume. (The way it works is similar to ones used in labs like this Biowave Personal Cell Density Meter although the price point we are looking at is much much lower.) As long as the vial is more that half full the meter can make a reading.

Cell density is typically expressed as Billions of Cell per Liter. Cell Density multiplied by volume gives you the number of cells in that volume. So if the device measured 110 Billion Cells per Liter and the sample was taken from a 2 Liter starter then you would know that your starter produced 220 Billion cells.

So the question is would you like to only know cell density, or would you like to the device to determine the total cell count as well?
Click to expand...

Ah, i think i understand now, for some reason in my head i was envisioning taking the measurement after the starter was done and decanted...your talking about making the measurement while everythings still mixed up..gotcha.

I think either of those works, the math isnt difficult. If its free to do on the hardware side go for it, otherwise i dont see a reason to increase the cost to multiply 110 by 2 and display that.
 
If it was around $100, maybe up to $150, I'd buy one. Like most others, I'm far more interested in cell count than SRM, but would take the SRM measurement if it didn't cost much more. And I am more than happy to do the multiplication myself if it reduces cost.

Any idea when you could get something like this to market? I've been checking craigslist for a cheap microscope, but I'd probably wait for your product if it realistically looks like it would come out not too far in the future.
 
What would the be a cost if made to 10%.

rhetorical question, just brainstorming, sometimes there is a expodentally increasing cost when shooting for better accuracy and maybe 5% is not needed.
 
sfish said:
..., sometimes there is a expodentally increasing cost when shooting for better accuracy and maybe 5% is not needed.
Click to expand...

That's a good idea, but in this case it would only shave a small fraction off the price. At the magnitude of production we are looking at for the kickstarter launch a large portion of the cost is the custom machining.

It's hard to say when the device will be available. We are in the design phase now.

Eugenio said:
If you need beta testers, I volunteer :)
Click to expand...

We're not looking for beta testers, but I am local to Boston and would consider doing a demo for Boston area brewers.
 
So does this tell you the cell density of viable cells only?

If so, this does sound awesome. When I've harvested from a starter multiple times, I'm assuming cell density and viability so it would be nice to have a more accurate value when making a starter. It would also be great for checking the accuracy of the online calculators for cell growth.

I would love it to be closer to the sub $50 range as I'd probably buy it without hesitation. If it was closer to $100, I'd probably wait for some holiday where someone doesn't know what to get me.
 
WoodlandBrew said:
Do you want a tool that can measure the amount of yeast in your starter or wort, and is easy to use?

More accuracy than a microscope and hemocytometer? Perhaps 5%, 1% or better accuracy?

Would you pay $100 or $200 for a device that measures cell density more accurately than a microscope and hemocytomter, and color to SRM and EBC standards? .
Click to expand...

If this meter is counting all cells viable + dead how can it be more accurate???
 
Hmmm sounds interesting. As for percent viable cells if possible it would be handy for repitching or for counts when stepping up....if the measurement is after a fresh starter though the viability numbers should be relatively high...at least to get you in the ballpark
 
I can guestimate my viability since I'm generally going to be measuring healthy slurry, and that's what I do with Mr. Malty anyway. The accuracy thing is probably not meant too rigidly, I'm guesing, and has more to do with the fact that when I have seen 3 brewers count cells on a hemocytometer they often come up with 3 different numbers.
 
I would love a homebrew-accessible tool such as you are describing. As other had said the SMR is less important to me than overall cost, but if the added functionality doesn't result in that much more of a retail price I would be okay with added features.

You thinking of using something like Kickstarter to get this idea past the design phase?
 
Sounds very interesting. I think $100 is pricy, but I'm a cheapskate. That said it would certainly go on my wishlist.

Stuff that you probably don't have answers to at this phase of the project but:
I'm guessing such a system works based on turbidity. How do you differentiate yeast from trub? Turbidity measurements are also affected by opacity of the liquid and dark solutions usually need a standard, so how can you compensate for liquids of varying color?
 
Turbidity is correct.
Automatic cell counters work by shining a certain color light through the solution and measuring how much makes it. Then using some empirical data you convert percent transmitted to cell density.
This is meant to be used on starter wort which is typically unhopped pale malt. You can account for any SRM interference by using wort as your calibration blank.
As far as trub, again this is meant to be used with unhopped wort that has been sitting for a few days. Anything bigger than protein or yeast will have settled out during fermentation, and protein will get zeroed out.

SRM would probably have to be done prior to bottling to avoid yeast/protein interference. It is also a pretty fault tolerant scale so I imagine if you took the reading as you siphoned to your fermenter it wouldn't be too much different.
IMO SRM is something even judges are going to eyeball so a paint swatch for the style is just as effective as a reading to the nearest tenth of a unit.
 
I don't want to go into too much technical until we are closer to completion, but guys are very close.

I've been tossing around different ideas on detecting viability, but so far don't have a solution that we could deliver.
 
I would need viability measurements to be useful to me. It's one thing to know there are 100 billion cells, but it's quite a bit different to know that only 25% are viable.
 
"When" in the process of counting could be important here. It doesn't take much sugar to get the live cells back into solution. Feed, stir, wait an hour and check.
 
I would need viability measurements to be useful to me...
Click to expand...
A simple addition and brief exposure time to methylene blue prior to measurement will give you what you want.
http://link.springer.com/article/10.1007/BF01568802

If you've got the time, and glassware(that +/-5% cylinder you have won't cut it) you can make your own yeast standards. http://www.phys.ksu.edu/gene/d2.html If you keep track of dilutions you should be able to calculate your original density. Likewise you would be able to make any dilution from the initial density on down.
 
I've created a summary of the questions and answers below. Let me know if I missed any questions that you still have.

What is it?
The yet to be named device is a cell density meter that also measures beer color. It provides an easy and accurate cell count of starters or yeast slurry.
How does it compare to a microscope and hemocytometer?
It&#8217;s much easier to use, faster, and considerably less expensive. Counting cells using a microscope is highly depended on the operator. If you asked three different lab technicians to count the same sample of yeast you are likely to get three different answers. Tests I have done indicate that variation in counting is 10% on average. The accuracy goal of this device is 5%. One advantage of the microscope is that viability staining can be performed. Our device may not be able to measure viability, but we do have some resources that will be listed in the manual for estimating viability of yeast throughout the brewing process.
How do you know it is accurate?
In addition to rigorous engineering analysis we will be testing the device with a set of standards. We will be using yeast standards but will also add a gradient of beer color, creating a two dimensional matrix of standards. These results will also be compared to counts using a hemocytometer.
Is it accurate in dark beers? How does it work?
Unlike other cell density meters, this device is specifically designed to compensate for beer color. Cell density meters, commonly used in laboratories, work by measuring the amount of light transmitted through the sample and correlating the measurement to cell density. This makes the device susceptible to error caused by the color of the liquid in which the cells are suspended. Our device employs additional hardware and software algorithms to compensate for beer color producing a more accurate cell count.
Can I see it work?
If there is enough interest there will be a demonstration of the device to Boston area brewers. We will also be producing a video of the device in action.
Will you be doing a Kick Starter?
Yes, without it we wouldn&#8217;t get off the ground. Many of the parts will require custom machining which can be very expensive in low quantities. Our target is to build at least 100 devices.
Can it tell the difference between yeast from trub?
The short answer is that it cannot tell the difference between yeast and trub. However, trub makes up only a small amount of the mass at the end of fermentation. The slurry from a five gallon (20 liter) batch of beer will contain about five trillion yeast cells.
Does it measure Viability?
Viability of yeast under various conditions that they may see through the brewing process is something that I have studied in length. The results may surprise you. Essentially there is very little drop in viability with refrigerated yeast even over months of time. The dominant factors effecting viability of yeast slurry harvested post fermentation is the amount of alcohol in the beer and how long it has been at room temperature.
Viability method: http://www.woodlandbrew.com/2012/11/counting-yeast-cells-to-asses-viability.html
Viability of Yeast in the refrigerator: http://www.woodlandbrew.com/2012/12/refrigeration-effects-on-yeast-viability.html
Viability of Yeast at room temperature: http://www.woodlandbrew.com/2013/01/abv-effects-on-yeast.html
How much does it cost?
Our goal is to produce a product that is accessible to the home brewer. It needs to be straight forward to use and reasonably priced. We are undertaking this effort because this is what we enjoy doing. We aren&#8217;t looking to make a profit on production, and I&#8217;m sure we aren&#8217;t going to be able to afford to &#8220;pay ourselves&#8221; for the countless hours that we are pouring into this project. We are doing our best to keep assembly labor as low as possible so the cost is mostly driven by materials. We will likely be able to produce this product for about $100 per unit.
Wow, that&#8217;s a lot of money is there another option?
There may be a DIY option available that would include just the sensor assemblies and programmed micro controller. This will likely cost less than $30. The rest would be up to you including the enclosure, power supply, sample vessel, and a few other things that are available commercially. We would provide the best instructions that we can, but support beyond that will be very limited.
 
WoodlandBrew said:
How much does it cost?
We will likely be able to produce this product for about $100 per unit.
Wow, that’s a lot of money is there another option?
Click to expand...

Considering I've thought about buying a microscope and hemocytometer for counting cells (and many homebrewers have), $100 sounds like a great deal if it's decently reliable.

Looking forward to hearing more.
 
Woodland, I agree w/ Shockerengr, that's cheaper then the current alternative homebrewers have. I wouldn't bother with that 30 dollar setup. Those customers are going to be your biggest service drain and your lowest profit margin...and I know you said "support beyond that will be very limited" but I think the vast majority of your support calls will be exactly those product purchasers.

K.I.S.S. is my recommendation. sign me up right now. I'll prepay.
 
So basically this is a power or intensity measurement of the reference laser, then compare it using the scattered diffuse light reflected by the yeast in the wort?

Wouldn't this also be affected by the protein in the wort as well? Not sure of relative size or reflectivity.

Trying to remember from my optics lab, but won't there be an upper limit on the accuracy as well? Or is it beyond the range of typical starters?
 

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