Thursday, July 10, 2014

Cell Density Meter

A product development team that I'm excited to be part of has started design of a beer color and cell density meter. Our team is composed of engineers and scientists with over 40 years of combined in field professional experience.  Below is a summary of the feedback we have received, but we still need to hear more about what you might expect.  We are looking forward to making accurate cell counts a reality accessible to the home brewer.

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’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’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:
Viability of Yeast in the refrigerator:
Viability of Yeast at room temperature:

How much will 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’t looking to make a profit on production, and I’m sure we aren’t going to be able to afford to “pay ourselves” 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.

Friday, June 13, 2014

Book Review

I'm really grateful for all of my readers who have bought a copy of the second edition of Brewing Engineering.  To date, over 200 copies of the second edition have been sold. If you have read my book, would you mind doing me a favor and leaving a review on Amazon?  Not only will it let others who are interested know what to expect from the book, but it will provide me with valuable feedback for future editions.

Friday, May 23, 2014

Fermentation Model

For my book I developed an excel based model for yeast growth.  This was based on experimental data, physical and biological properties, and also a few "scale factors" to align the model with measured data.  Most of the data is from beers with an OG from 9°P to 16°P (1.036 to 1.064) at temperatures near 70°F (25°C) using standard pitch rates of US-05 yeast and Briess Malt extract.  The model should hold up fairly well near those operational points, but I am sure there will be some deviation in nearly every case and significant deviation in a few cases.

Description of Graph
The lines are generated by the model.  The squares and diamonds were measured experimentally.  The cells that have an orange background are intended to be changed. 

Total Sugar - Sugar concentration in degrees Plato (multiply by 4 to get brewers points)
Single Chain - Component of Total sugar that is simple sugar
Two Chain - Component of Total sugar that is more difficult to ferment 2 chain sugar.
Sugar - Measured sugar (Refractometer corrected for alcohol)
Yeast Suspended - Billions of cells per liter (as counted on a hemocytometer)
Total Yeast - Calculated total yeast population
Yeast Suspended - Calculated yeast remaining in suspension (note that this is highly strain dependent, but can be adjusted in the model)
Growth - Billions of cells grown per day.

My book goes into more detail about the application of this model and how this graph can be used to better understand yeast growth.

Yeast Growth Fermentation Model

Saturday, May 17, 2014

Vacation Beer Highlights

Thankfully, my wife understands my passion for good beer, so as any beer lover would do we made sure to work some great beers into our vacation.  We tried some stellar beers, but not every place was a beer haven.

The first beer stop was Brown's Brewing Company, located in Troy, New York.  ( All of the beers here were excellent, as my smile in the photo above may indicate.  A flight of 6 beers was roughly the same price as a pint and you get to pick the beers, making this a great option.  The beers, along with my comments, from left to right are:
1) Pale Ale - Almost as hoppy as a typical IPA
2) Cream Ale - By far the best cream ale I have ever had
3) Belgium Wit - leaning more toward a fruity American Ale, but one of the best American Belgium style beers I have tried.
4) Brown Ale - Perfectly true to the style.  Leans a little more to the northern brown, with a prominent caramel flavor.
5) Black Lager - About as good as I could imagine a black lager could be:  A nice lager with black malt for color.  In my opinion, this is style is likely to be a passing fad.
6) Oatmeal Stout - An excellent example of the style.  This balances the black malt well with all of the other components of a stout.

In Buffalo we visited Blue Monk. (  The beer selection here is outstanding with over 30 beers on tap and over 100 in bottles.  There are four different flights to choose from: Hop head, America, Belgian, and Dark.  We went with the Belgian and the Dark.  All of the beers were excellent, and each one flowed nicely to the next.

We even found references to beer in some unsuspecting places. The Buffalo Botanical Gardens were growing Brewers Gold Hops!

There are some places that you can't expect to find great beer despite what the menu says.  When I inquired at the bar, the bartender responded:

"Local and Craft beer?  Lets see we have Bud... wait, craft beer?? umm..."

Sunday, March 30, 2014

Extract Recipe Calculator

Why would anyone make yet another recipe calculator?  There are two major short comings of existing recipe formulation tools that stand out.
  1. Attenuation is normally fixed at 75% and is independent of the ingredients.
  2. Salts are generally not accounted for, especially the salt contribution of the extract.
Experiments have shown that the type of sugar in the wort directly effects the attenuation of the beer.  Simple sugars, such as corn or cane sugar, are 100% fermentable.  Maltodextrin does not ferment, and Briess DME is designed to be 75% fermentable.

Before Dry Malt Extract is dry it is wort, the same as it would be when making beer.  To make wort malted barley and water is mashed and then sparged.  The difference is that after the wort is made, instead of being fermented, the water is removed.  All of the salt that are present in the water are left behind in the dry malt extract.  The folks at Briess were kind enough to tell me exactly what to expect with their products.

This tool takes these factors into consideration. 

Extract Recipe Calculator.xlsx

Using the Calculator

Orange cells are meant to be changed.
Bold Orange text is calculated.

Volumes for your recipe are entered in column B.  Ingredients can be selected from the drop downs in column D.  Feel free to add more ingredients on the "LookUp" tab, but keep in mind that for things too work correctly they must remain in alphabetical order.

Wednesday, March 26, 2014

Kindle Edition of Brewing Engineering

Coinciding with the release of the 2nd Edition of of Brewing Engineering,  I have also released a Kindle Edition of Brewing Engineering.  The Kindle Edition will be available for only $3.99 on  Get your copy today!

Sunday, March 23, 2014

Simple Lager

The weather is just right for brewing a lager.  The water bath is stable at 49°F, a good temperature for SafLager S-23.  The beer should finish with a nice malty flavor.  At temperatures above 55°F S-23 can get a little fruity.
Time has been a precious commodity these days so this batch is going to be an extract brew.  If you do it right, the quality of beer made with extract is on par with an all-grain beer.  The cost is about the same as well.  There are a number of hidden costs with all grain brewing such as trub loss and the cost of fuel that are often left out when comparing overall cost.  When making a batch of all grain beer it costs me about $5.00 in fuel alone.  If there is interest I'll write about that more in another post.

This beer will be a very simple base beer using my quick brew method. (See my book for details)

6lbs of Briess Pilsen DME.
1 oz of Challenger hops boiled in a quart of water for an hour.
S-23 SafLager

Using the simple pitching method outlined in my book I expect the cell count to be about 100 billion cells.  This can be verified with my Amscope microscope.

I expect this to a nice clean drinkable beer at about 5% ABV.  To add variety I have been developing "beer boosters" added when the beer is served that push the base beer into different styles.