Start Brewing for Less Than 100 Bucks.

The Essentials:

• 6.5 gallon Fermenttion Bucket
• Air Lock
• Bottling Bucket
• 1 Hydrometer
• 6 feet of 5/16" Vinyl Tubing
• Butterfly Capper

This kit seems to have it all, and at a great price:

  This is the kit I cut my teeth on:

What you'll need to round up

• Your spaghetti pot.  (6 quarts is a reasonable size)
• Two cases of pop top brown beer bottles with a long neck and a skirt.

You don't need an immersion chiller or a thermometer when doing a partial boil.  For a five gallon batch of ale boil 1 gallon of water and combine with 4 gallons of refrigerated water in the fermentor.  The resulting temperature will be the correct pitch temperature for most ales.

The three most common mistakes made by first time home brewers are:

1. Lack of fermentation temperature control.
2. Insufficient yeast.
3. Use of tap water with extracts kits.

To control the temperature put the fermentor in a plastic bin with about five gallons of water.  This will hold the temperature very close to ambient temperature.  Choose a kit that ferments well at your ambient temperature.  If your basement is near 55 degrees choose a Lager.  If it is near 60 degrees choose a hybrid like a Cream ale or Kolsh.  65 is ideal for just about any ale.  70 is best for Saisons and some Belgium beers.

When choosing a kit look for one that uses dry yeast and has an ABV of 5% or less.

One packet of dry yeast contains about 150 billion cells.  This is sufficient for up to a 1.050 starting gravity which is less than 7 pounds of extract in a five gallon (19 liter) batch.  The result will be a beer less than 5% alcohol by volume. 
Because extract is made from an all grain mash it has all of the minerals needed for the beer concentrated in it.  The major manufactures, Briess and Muntons, both are located in areas that have great brewing water that already have enough minerals.  By using tap water, or spring water you are adding extra salts that will end up leaving your beer with a kind of a twang.  Use Distilled or Reverse Osmosis water for extract brewing.  You should be able to find it for less than a dollar a gallon.

 55°F        60°F
65°F         70°F

Step up your game

• Autosiphons ($10)
• Thermometer for measuring pitching temperature ($8) 
• Kegging setup

Kegging take much less time than botteling.  Kegging can take as little as 15 minutes where botteling can easiliy take over an hour. When it comes to kegging most people will recomend that you skip the small kegging setup and move right to the soda keg and CO2 tank.  For me, I don't have the space (or cash) to sink into a soda keg setup, so what I use is the tap-a-draft system.  My brother uses the Party Star system and he loves it.  Another advatage of a mini keg system is that they are easier to bring over to a friends house than a soda keg setup.

These are the ones I have and they work great!

Making better beer and brewing toys.

• bin or cooler to use as a water bath for fermentation temperature control.
• Refractometer. Much easier, faster, and smaller sample size required.
• aquarium heater to ferment ale's in the winter 
• scale for grain and extract
• scale for salts and hops 

These are the items that work for me, and what I have my eyes on:

Oxygenation with Hydrogen Peroxide

Yeast require oxygen in order to synthesize compounds during growth.  The lack of oxygen will therefore become evident if the yeast are put in conditions that with adequate oxygen would produce large amounts of growth.  In order to highlight the use of oxygen in these tests a high gravity wort will be used and drastically under pitched.  If the free oxygen in hydrogen peroxide can be utilized by the yeast then this should make it evident.

The Test

The hydrogen peroxide solution at the pharmacy here is 3%.  For each molecule of 2(HO) there is one Oxygen molecule that can disassociate.  It takes two of them to make oxygen gas.  With some molar math this means that the solution available at the drug store is equivalent to a 7000ppm O2 solution.

For the tests these will be diluted down to more reasonable amounts of oxygen.  350, 175, 88, 44, 22, 11, 5, 3 and zero will be used.  Each test will be done in triplicate.

All tubes will be inoculated with a 21°P wort and 1 million cells per ml.  (under pitching by a factor of twenty in a very high gravity wort.)

All tubes will be done in triplicate.

All of the tubes initial gravity, final gravity and final cell volume will be recorded.  A cell count will be conducted on three of the tubes with the lowest volume of cells and three tubes with the highest volume of cells. From this information final cell counts will be derived for all 27 tubes.

In addition, daily cell counts will be preformed on two additional tubes.  One containing no additional hydrogen peroxide and the other containing the 11ppm oxygen equivalent using hydrogen peroxide.  Daily cell count and gravity will be checked.

The results

Hydrogen peroxide was effective at adding oxygen to the wort, but did not improve attenuation.  The toxicity of the hydrogen peroxide was detrimental to yeast growth.  The optimum level was an equivalent of 50ppm of oxygen although at this level the results were similar to adding no oxygen.  The high gravity wort with low pitch rate took 12 days to complete with and without the added oxygen, although fermentation without added oxygen in the form of hydrogen peroxide was significantly faster.

The Practical Brewer

The Practical Brewer has been an excellent resource for brewing.  The chapters are all written by renowned member of the professional brewing community composed of both brewers, instructors and scientists.  This is the best text book on brewing that I have read.  Everything is covered in detail from wort production to fermentation. 

If you are serious about brewing, whether as a home brewer or professionally, this is a book you'll want to have in your library.

How Beer Saved the World

Perhaps the title is a little far fetched, but this is entertaining and informative none the less.  This feature length video makes for a nice way to unwind on the weekend.  Take a trip through time to discover how beer has shaped civilization and led to numerous inventions.

Yeast Propogation with Aerobic Respiration

The primary goal of fermentation is the production of alcohol, while the goal of propagation is increasing the yeast biomass.   On one hand, anaerobic yeast respiration converts sugar into alcohol, carbon dioxide, and some energy.  Aerobic reparation, on the other hand, converts sugar and oxygen into water, carbon dioxide and about twenty times as much energy.  The real difference between these two is that with oxygen more energy is produced.  Without oxygen more alcohol is produced.

The two things that yeast need from the wort to make new cells is material (sugar) and energy.  While both of these are available during both aerobic and anaerobic respiration there is much more energy during aerobic respiration.  This is why a stir plate, that provides constant oxygenation, is commonly used for starters.

Oxygen is good for propagation, but how much is required, and how can it be used to maximize cell growth?

Aerobic yeast respiration is as follows:
C₆H₁₂O₆ + 6 O₂ → 6 CO₂ + 6 H₂O + 31 ATP (see footnote 1)
180g C₆H₁₂O₆ + 192g O₂ → 264g CO₂ + 108g H₂O + 31 ATP

Converting from moles to grams we can see that for every gram of fermentable extract 1.07 grams of oxygen are required for aerobic respiration.   For a 10°P (1.040) wort that would be a whopping 107,000ppm!  With pure oxygen gas the saturation point of water is only 50ppm.  So in terms of aerobic respiration, there is no practical limit to the amount of oxygen that can be utilized.  Oxygen, however, is toxic to yeast in high concentrations.

Because oxygen is always in short supply anaerobic respiration dominates the metabolic activities.  For this reason, the anaerobic reaction very closely resembles Balling observation.  When the reaction is converted to moles it can be seen that the "losses" that balling describes are the sugar converting to other materials.

Anaerobic Respiration:
C₆H₁₂O₆ → 2 CH₃CH₂OH + 2 CO₂ + 2 ATP(see footnote 2)
1.9553g C₆H₁₂O₆→ 1g CH₃CH₂OH + 0.9553g CO₂ + 2 units ATP

Balling Observation:
2.0665g C₆H₁₂O₆ → 1g CH₃CH₂OH + 0.9565g CO₂ + 0.11g biomass (see footnote 3)

The Carbon Dioxide is virtually identical and the difference in glucose mass is almost exactly the yeast biomass. 

If the two things that yeast need are sugar and energy to reproduce then how much more yeast would be generated from aerobic respiration.   For every 2 units of ATP 0.11g of yeast are generated.  If there were 31 units of yeast then 1.705g of yeast could be generated.  This would require 3.6603g of sugar and adequate oxygen.   Anaerobic respiration produces 0.053g of yeast per gram of fermentable extract.  At 20 billion cells (dry mass) per gram that's 1 billion cells generated per gram of extract.  Aerobic respiration could produce 0.4658g of yeast per gram of  fermentable extract. This makes 9.316 billion cells per gram.

With adequate oxygen the yeast propagation could be almost 10 fold above what is typical of fermenting beer!

So how can we get anywhere near the 107 thousand parts per million, and what is the maximum the yeast can tolerate? Don't worry, I've got a plan and a set of experiments to prove it.

(1) http://en.wikipedia.org/wiki/Cellular_respiration
(2) http://en.wikipedia.org/wiki/Ethonal
(3) Balling C. J. N. 1865. “Die Bierbrauerei” Verlag von
Friedrich Temski, Prague, CHZ. As cited in:
MODELING OF ALCOHOL FERMENTATION IN BREWING – SOME
PRACTICAL APPROACHES, Ivan Parcunev, Vessela Naydenova, Georgi Kostov, Yanislav Yanakiev, Zhivka Popova, Maria Kaneva, Ivan Ignatov http://www.scs-europe.net/conf/ecms2012/ecms2012%20accepted%20papers/mct_ECMS_0032.pdf

AWS-1KG

This scale kicks the pants of the other scale I have for weighing brewing salts.  It displace the weight in 0.1 gram increments, and can also display in oz.  The accuracy is listed as 0.1g as well, meaning that when it says 1.7g it is between 1.6 and 1.8 grams, and testing seems to confirm this for most weights.  There was slightly more error below 20 grams although for the money, I don't think you can beat it.

Out of the box the scale was accurate to 5%, but the scale can be calibrated with a 500g calibration weight.

One odd thing I noticed is that the scale seems to be fairly unstable at weights less than one gram.  By shifting the substance on the plate the weight value will change by up to 0.2g.  This is so small it shouldn't be an issue.

Overall, I think the scale is great, and an excellent value!

Chicha, Brewmasters

 

Dog Fish Head is known for being pretty far out there when it comes to beer, and this episode is no exception. Learn about the origins and mysteries of Chicha. Corn doesn't have enzymes in it to convert the starch to sugar like barley does.  Find out where the Dogfish Head got these enzymes from when making this ancient beer.

Take a trip with Sam Calagione to South America to discover how it is made now, and how it was made in the past.

Starter Calculators Revisited

YC-I : Yeast Calc (same as Mr. Malty) with "Intermittent Shaking"

YC-N : Yeast Calc (same as Mr. Malty) with "None" selected for Aeration

YC-SP : Yeast Calc (same as Mr. Malty) with "Stir Plate" selected for Aeration

S-04 : Fermentilist Safale yeast shaken only at the start of fermentation.

US-05 : Fermentilist yeast shaken only at the start of fermentation.

Balling : Karl Ballings observation applied to starters.
Wyeast : Calculator from W Yeast site

This data is a compilation cell counts on more than 50 starters.  The lower inoculation rate starters have a higher spread of values.  This deviation is  likely error due to the smaller magnitude of cells counted.  All starters were shaken vigorously at the onset of fermentation but otherwise left still.

When it comes to still starters, the easiest and most accurate way I have found to calculate cell growth is with simple multiplication, but if you have to use an online calculator then using the "intermittent shaking" selection seems to be the most accurate.

To calculate the number of cells to expect in a still starter the following eqation can be used:

Cells Grown = 10 * Volume of starter (in litters) * Gravity of starter (in degrees Plato)

Although only Yeast Calc is shown here the other two popular calculators have a similar growth curve.  Mr. Malty is almost identical in results to Yeast Calc because the latter is a derivation of the former.  The Wyeast calculator has a similar curve to the other two popular calculators.

Low Inoculation Rates

One thing that is most apparent when comparing measurements to the calculators is the performance at low inoculation rates.  The calculators all show considerable roll off in growth at inoculation rates less than 20 million per ml.  This could be due to time.  The lower the inoculation rate, the slower the fermentation will progress.  If the starter was used 48 hours after inoculation the cell count may very well be at the low levels shown by these calculators. 

Moderate Inoculation Rates

The center portion of the calculators is very flat.  For inoculation rates of 40 to 140 most of the curves are fairly flat.  This fits well with what would be expected of normal fermentation.  The primary limiting factor of cell division is available sugar making the cell growth directly proportional to sugar.  Mr. Malty and Yeast Calc have setting for various types of aeration.  Given more oxygen,  yeast will preform aerobic respiration. (1)  The larger amount of energy produced from aerobic reparation allows more bio mass to be generated.  In the presence of high sugar concentration the production of biomass is the preferred. (2) 

Cell growth is proportional to both sugar and available oxygen.

High Inoculation Rates

At high inoculation rates the calculators show diminishing return.  This indicates that the yeast are reaching a maximum cell density.  At cell density of 200 million per milliliter cell productions slows significantly.  At a cell density of 300 million per milliliter cell growth nearly stops.

(1) http://en.wikipedia.org/wiki/Pasteur_effect
(2) http://en.wikipedia.org/wiki/Crabtree_effect

Acid Washing

Using acid is no joke and requires proper handling. Many commercial breweries use sulfuric acid, although for home brewing this is likely not the best choice. Even Star San in its concentrated form, can be extremely caustic. Luckily for home brewers this procedure uses prepared Star San.
Starsans, when properly prepared is a 0.08% phosphoric acid solution. (Think about the concentration.  Even with just a trace of acid it is strong enough to kill nearly all bacteria)  The pH of this solution is between 2 and 3 which is just about the recommended pH for yeast washing. If a small portion of yeast is combined with a much larger portion of star sans the pH will stay in the yeast washing pH range. If this yeast slurry with acid was added to the beer it would likely be noticeable sour. To prevent this, the acid can be neutralized.

Phosphoric acid not technical a strong acid although it is quite powerful with a pKa of 2.1(1).  If this is combined with a small amount on a weak base the acid will pull all of the needed OH ions from the weak base to the point when all of the hydrogen ions have been cancelled. Because the ions to not disassociate easily from the weak base creating a solution that is too alkaline is not a concern.
Another advantage of using a stronger acid with a low concentration, That means the highest concentration of salts in also very low. One weak base that nearly everyone already has is baking soda, or sodium bicarbonate. This has a pKa of 10.3which is much closer to the neutral pH of 7.  When sodium bicarbonate reacts, it breaks down into carbon dioxide and sodium hydroxide. Three salts can be formed from the combination of sodium hydroxide and phosphoric acid.(1) These are monosodium phosphate, disodium phosphate, and trisodium phosphate. These salts are fairly soluble in water, and will also be in low concentration. Crashing and decanting the yeast will remove a large percentage of this salt.

Recently I put this to the test.  A slurry was selected that had low viability of 50%.  It also had  easily distinguishable bacteria.  These were 15-20um long rods that stain with Methylene Blue.  Two starters were prepared, one washed with Star San and the other was washed with water.

The washed yeast progressed a little slower than the yeast that was not washed, which can be expected.  Both of them ended at about the same gravity and cell count.  No bacteria was observed in the washed yeast at the end of propogation. 

In summary, it looks like this is an easy way to truly wash yeast.

1. Add equal parts slurry and prepared Star San to a container and allow to rest for one hour.
2. Add a pinch of baking soda to the container to cancel the acid.
3. Add DME and water to create a starter and ferment to completion.

Side by Side Starters 4 of 4

There are three big take aways from this collection of data.

1. For reasonable inoculation rates and gravities cell growth is not a function of inoculation rate or volume.  Cell growth is simply a direct function of sugar, and may be more accurately predicted by observing sugar consummation.
2. Yeast taken from storage at 40°F (5°C) can out preform yeast taken from an active starter likely due to the glycogen content of the yeast.
3. Attenuation is a function of both inoculation rate and gravity.  Higher inoculation rates and lower gravities lead to higher attenuation.

Growth

Cell growth observed over this wide range of inoculation rates and initial gravities showed cell growth proportional to the amount of initial sugar present.  In the case of the active culture of S-04 7.2 billion cells were grown per litter per initial degree Plato.  Considering that the average attenuation was 62% this indicates that 11.6 billion cells were grown per liter degree Plato of consumed sugar.  This tracks very well with the daily observations.  In a similar fashion the inactive starters grew 10.4 billion cells were grown per litter per initial degree Plato with an average attenuation of 68% making 15.3 billion cells grown per litter degree Plato of sugar consumed.  Both of these starters closely followed the equations derived from Ballings observation for starter cell growth.  Based on these observations the equation can be adjusted to account for the higher cell growth that is likely linked to proper aeration at the onset of inoculation.

Cells Grown = 14 * Volume of wort (Litters) * [Initial Gravity of wort (°P) - Final  Gravity of wort (°P)]

Glycogen

The yeast taken from refrigeration outperformed the yeast taken from a starter in terms of total attenuation and in cell growth.  When fermentation is allowed to run to completion yeast cells will build up a glycogen reserve.  It is possible that this extra glycogen allowed the refrigerated yeast to grow more cells given the same amount of sugar.  Further testing would be required to confirm this including measurement of the glycogen levels.

Attenuation

The percentage of sugar consumed seems to be a function of both the initial gravity and the inoculation rate.  A linear fit for these two parameters shows an excellent r squared fit of 0.9139 and 0.9795.  Although this shows wonderful correlation I am hesitant to say there is causation.  There are a other considerable factors, such as temperature, that are not accounted for here.  The equation also breaks down quickly at inoculation rates beyond the data set used.  It does seem reasonable at inoculation rates and gravities typically used for fermentation of beer.

The following equation can be derived from the linear fits:

A = Real Attenuation (as a decimal.  ie 0.71 = 71%)
G = initial gravity (in °P)
I = Inoculation rate (in million per ml)

A = 9.54E-4(G)-2.44E-4(G)(I)+4.23E-3I)+5.19E-1

Shaped markers are measured data points. 
The number of cells at zero initial gravity is the inoculation rate. 
The "Active" chart represents data taken from an active starter.
The "Inactive" chart represents cells taken from refrigeration.



Real Attenuation in %sugar by weight.
Each column is the number of cells used for inoculation. 
Divide by 10ml for the inoculation rate.