The Yeastmongers

A hydrometer is an instrument that measures the specific gravity of liquids, namely the ratio between the density of the liquid and another liquid of reference (like water).

Beer is denser than water, so its specific gravity is always more than 1. Beer density is caused mainly by its sugar contents, so a higher specific gravity means that the beer has more sugar. A beer with 1 as specific gravity has no sugar.

Beer fermentation converts sugar into ethanol and CO2, so you can know if the fermentation has stopped if you see the sugar content stabilizing.

In general, hydrometers are cylinders with a weight at the bottom. The cylinder floats in the liquid, but it sinks depending on the liquid density. This correlates with specific gravity.

An electronic hydrometer is useful because you don’t need to extract a sample of your beer to measure specific gravity. The hydrometer can be always in your fermenter and wirelessly communicate its value.

One famous electronic hydrometer is the Tilt.

The Tilt doesn’t stay erect like a typical hydrometer, but it tilts in a certain angle correlated with specific gravity.

Electronically, the angle can be measured using a three-axis accelerometer:

The force of gravity always acts perpendicular to the earth's surface. So when an object is tilted at an angle, part of that force acts along the X axis of the object, and part acts along the Y axis. The X-axis acceleration and the Y-axis acceleration add up to the total force of gravity using the Pythagorean Theorem. Since you know that, you can calculate the portions of the acceleration using sines and cosines.

Source

iSpindel is an open-source electronic hydrometer project that follows these same principles. It uses a MPU-6050, a cheap chip that combines an accelerometer and a gyroscope.

This chip is included in a variety of sensor boards ready to use. For this project we’re going to follow the iSpindel specs, so we’ll use a GY-521 board.

Cost with shipping from AliExpress: 1.56€.

This weekend I brewed a dunkelweizen, following a recipe by the new book by Chris Colby from Brew Your Own. I introduced the recipe in my Beersmith and then converted it to my equipment (12L eBIAB) and mashing profiles.

I’m still always tuning my brewing process and for this batch I decided to get rid of mash out. Why?

Well, mash out is a process useful when you want to stop the enzyme action but in pure BIAB we don’t need that, because we’re not going to do sparging and we’ll increase anyway the temperature to get the goodness boiling.

Sometimes there’s a second reason to do a mash out: dissolving sugars. But this is only useful if you'r brewing something over 1,300.

So, I mashed for 90 minutes, took out the bag, and then simply got the wort boiling. My expected OG was 1,054. I got 1,043. Fail.

I have two hypotheses:

Maybe I grinded too thick. In my early BIABs I grinded very thin, but I changed it because I was getting some astringency.

Or maybe I need the mash out. The mash out is an extension of mashing time: some minutes to get the water to the mash out temperature and then ten minutes more where conversion is still happening.

So, in my next batch I’m going to grind a little thinner and I have two possibilities:

Mash for two hours, instead of 90 minutes.

Do a mash out as I did in early BIABs.

If you use Twitter start following me!

One of the most common questions in the BeerSmith forums, apart from why the heck the software uses this efficiency approach, is how to calculate it to set up an equipment profile.

“A good start is 72%”, says BeerSmith configuration wizard, but how we tune up this value?

Apparently, it seems that there isn’t any way to calculate the brewhouse efficiency from measured values in a brewed recipe but… there’s a hidden one! And this is Brad Smith himself explaining it 13 years ago….

To see the "Actual Efficiency" for all of your recipes, perform the following steps:

1. Select  the "My Recipes" view 2. Choose "Customize Columns" on the "View" menu. 3. Select and add the field called "Actual Efficiency" to your view.

That's it -- you will now see the total brewhouse "Actual Efficiency" calculated from your measured "Original Gravity" displayed as a column on your recipe views.

This weekend I did a second all grain batch with my eBIAB system (a Weissbier).

Two changes in the equipment, though.

First “we” sewed a finer mesh bottom to the bag. In my pure BIAB process I don’t sparge, so I need to delegate all the filtering to the bag.

Second, I improved the mash temperature control.

My electric kettle has a thermostat, but this type of temperature control is pretty dumb: if it gets to the desired temperature (for example 67ºC) it turns off the element; but the thermal inertia keeps heating the liquid and you’ll never get the correct temperature.

So I decided to install a PID, a proportional-integral-derivative controller. This piece of equipment has two advantages:

It uses a smart prediction system (that maybe I’ll talk about it some other day) to adjust the temperature and control the heating element. It studies your kettle thermal variables and adjust three parameters to predict the heating behaviour.

It’s not a dumb ON/OFF switch. It treats the heating element as a diffuse system; for example it can turn ON only to 30%. How it does that? Well, turning on and off constantly and playing with the frequency.

The PID is so fast turning ON and OFF that a typical relay would burn. So a SSR (Solid State Relay) is needed, with a good a heat sink.

This system is then connected to a RTD (Resistance Temperature Detector), that in my setup it goes throw the pot lid to the liquid.

As a temporary setup, I build the controller in a classy ice-cream box…

I made some changes in the mashing process too. Now I heat the water until strike temperature; then I turn off the system, add the bag and stir. I put the lid and the system is turned on again. Mashing for 90 minutes and then I do a mash-out to liquefy for 10 minutes. Turn off the system again, stir a lot, get out the bag, let it dip and begin the boil.

In my last batch, without mash-out I got a 72% mash efficiency. This time I got a 77%. Pretty decent to me.

Batch AG-005RC (10,00 l) Based on Biere de l'Inde (Brewing Classic Styles)

English IPA (Pale Commonwealth Beer) 5,5 % ABV / 46,0 IBUs 1,056 SG - 1,016 SG Calculated Mash Efficiency: 73,2 %

Grains 2,67 kg Pale Malt (BestMälz) 5,0 EBC 0,11 kg Biscuit (Dingemans) 55,0 EBC 0,11 kg Caramunich I (Weyermann) 90,0 EBC 0,11 kg Wheat (BestMälz) 4,5 EBC 0,08 kg Cara Bohemian (Weyermann) 190,0 EBC

Hops 21,00 g Northern Brewer [7,30 %] - Boil 60,0 min 11,00 g Fuggles [5,20 %] - Whirlpool 20,00 g Goldings, East Kent [6,00 %] - Dry Hop 3 days (in primary)

Yeast 1,0 pkg Nottingham (Danstar) re-hydrated

Fermentation and Bottling 2 weeks at 19º. Bubbling started in 18h. Lasted 3 days. Primed with 45,5 gr of table sugar.

I created a new Tumblr:

New Homebrew books

The title is self explanatory.

I found myself looking for new brewing books to buy and I didn’t find any good curated resource with novelties. So I created one.

Haha!  How is this even a thing we’re talking about?  Direct quote from Colby’s article (which is backed up by the data I found at the CDC’s website):

“In the US, with over 300 million people, there only around 20 cases of food-borne botulism in adults per year“

That’s right!  Your risk of contracting botulism in the USA is less than %0.00000001 (one one-hundred-millionth of one percent).

If you’re an Aussie worried about no-chill, there is only about once case of botulism each year reported in Australia according to Victoria’s health hub. in a population of about 23 million, your risk is also less than one one-hundred-millionth of one percent.

To put that in perspective, YOU ARE MORE THAN 12 TIMES MORE LIKELY TO BE STRUCK BY LIGHTNING THAN YOU ARE TO GET BOTULISM! (source)

Yup, that’s true. But from another article from Chris Colby:

The degree of risk associated with storing boiled wort is not known. In the US, the number of deaths each year due to botulism poisoning (the median is 23) is less than the number of deaths due to lightning strikes (the average is 93). I’ll hazard a guess that you don’t live in fear of getting hit by lightning. Neither do I. But I’ll also guess that when a thunderstorm approaches, you don’t grab a metal tennis racket and climb the nearest tree, either. It’s just common sense. Even if you did climb a tree with a metal racket, the risk of getting hit by lightening is low. It’s low, but it’s also a dumb risk.

Disclaimer: I’m not an expert on this topic. This is information from Internet and papers collected in a personal research. Be careful if you take any decision based on this post.

One of the common discussions in forums about the no-chill practice is if wort stored in a cube can be an appropriate environment for the development of Clostridium botulinum.

C. botulinum is a bacterium that produces botulinum, one of the most lethal neurotoxins known. Botulinum infection results in botulism, that causes flaccid paralysis, with muscle weakness, double vision, difficult to speak… and death.

Let’s investigate this little dangerous guy. It’s an anaerobic bacterium, meaning that it does not require oxygen for growth, like yeast; but C. botulinum is obligate anaerobic: it dies with oxygen exposure.

But wait, C. botulinum can form endospores. Endospores, you say?

Endospores show no detectable metabolism and can survive extreme physical and chemical stresses, such as high levels of UV light, gamma radiation, detergents, disinfectants, heat, freezing, pressure, and desiccation. In this dormant state, these organisms may remain viable for millions of years,

(from Wikipedia)

Ok, we have, then, three guys: the bacterium, its spore stage, and the toxin. The bacterium can’t survive with oxygen, so we can forget about it: when we are introducing our wort in the no-chill cube there’s no C. botulinum.

What about the toxin? Well, the toxin is destroyed at 85ºC. So boiling during five to ten minutes is enough to get rid of it. We are free of toxins in our cube too.

The endospore is the tough one. We can have some of them in our wort and we’re going to seal them in the cube.

Eating the spores is not dangerous and not the point of this discussion (eating them it’s not a no-chill problem, but a general food problem). Don’t worry: our digestive tract is too acidic for them to grow (but be careful with newborns, they have low-acid digestive systems that can be a good environment for the spore).

So we are isolating the problem here to a concrete question: can the highly resistant spore germinate in our low oxygen sealed wort and generate the neurotoxin?

The spore can’t grow in acidic conditions (PH less than 4.6), but our wort is not as low.

Neither can’t grow with the presence of oxygen, and our cube is made of plastic so it’s a little permeable; but

The small amount of oxygen permeability that plastic shows is not sufficient to let in enough oxygen to inhibit C. botulinum. Oxygen levels over 2% are required for this.

(from Beer and Wine Journal)

Bacterium can’t grow in high salt or sugar concentrated environments. Osmotic pressure can kill them. This is why C. botulinum spores can’t germinate in honey and generate the neurotoxin. Some people states that the wort sugar content is too much for the bacterium, but I’m not really sure if this is true.

Honey has more than a 50% of sugars (water is only 14-18% of the concentration). A wort with 1050 SG will be equivalent to 12,4 °Bx, meaning that there’s one 12,4 sucrose grams for every 100 grams of solutions. Is this enough?

I won’t talk about water activity induced by sugar concentration. First because I don’t really understand its thermodynamics and second because although C. botulinum can’t grow with water activity lower than 0.85, neither Saccharomyces cerevisiae.

But we have hops. Hops are antibacterial:

hop extract is useful as an antibacterial agent against the dangerous pathogens Clostridium botulinum, Clostridium difficile, and Helicobacter pylori at levels below that at which a flavor from the acids contained therein is objectionable.

(from patent Antimicrobial activity of hops extract against Clostridium botulinum, Clostridium difficile and Helicobacter pylori)

Are hops enough to prevent C. botulinum germination? Sadly, this is an open question for me.

Botulism is rare. In all USA an average of 22 cases of foodborne botulism are reported yearly. There’s no known case of no-chill related botulism in the world.

But the risk is there.

Are we overanalyzing this “new” practice? Are our kegs or bottles dangerous too?  The common sense says that the alcohol concentration is high enough to prevent germination, but bad news:

Growth and neurotoxin production were delayed by an ethanol concentration of 4% ethanol and completely inhibited by a concentration of 6%

(from Effect of ethanol on the growth of Clostridium botulinum)

Is the remaining yeast in the bottle enough to compete with the bacterium? Will the 4.0ph be enough to prevent germination? It seems so, but who knows.

Chris Colby, who panicked everybody with the Storing Wort Runs the Risk of Botulism article added something in the comments

It takes at least 3 days for botulism to grow to the point where it can be a problem.

Brewing a classic English IPA with my eBIAB system for the first time.

And no-chill:

This is the new spigot configuration for my electric pot (based on The Electric Brewery)

A: Locknut (3/8″) B: Washer (3/8″) C: Silicone o-ring (16x22x3) D: Washer (3/8″) E: “Machón” (3/8″ - 3/8″) F: Two piece ball valve (3/8″) G: Junction (3/8″ to 12mm) H: Silicone tube (10x14mm)

All joints sealed with teflon tape.