WPB

Hard to Find Answers to Simple Questions

What is the best way to store my bulk grains?

Easy right? Put ‘em in a bag and keep ‘em cool. Not so fast. The basics of grain storage are: place them in an air tight container, keep them away from heat and light, and keep them dry. In a perfect world this works fine, but no brew day is perfect and neither is the world. Grain has something in it that we don’t like to talk about – of course all fresh foods have this potential. Bugs! Well, bug eggs. Gross right? It's a good thing we boil the wort. In reality, these bugs are not harmful in the least. In fact, many countries eat bugs as a great source of protein. Let’s get back to the topic. Granary weevil, flat grain beetle, rice weevil, saw-tooth grain beetle, grain moth, etc. are all potential pests in the grain we so love – particularly pale or base malts (roasted malts need not apply). After the grain is kilned, it has a very low moisture percentage, < 5%. At this level, the eggs do not hatch. It also helps to keep it under 65 F.

 

 

 

However, I live in a warm, humid state. Keeping malt at 5% moisture and under 65 F is not possible for me without refrigeration. Therefore, I must kill the eggs before storage. There are two ways to do this: heat or cold. I take all my grain (two 5 gallon sealable buckets) and place them both or one-at-a-time in a “deep freeze” for 3-4 days. Then I remove them from the freezer, keeping the lids on to prevent condensation, and let them warm to room temperature (75 F). That’s it. No bug problem. The cold causes what little moisture there is in the eggs to crystallize and rupture the embryo.

 

If you are not fortunate enough to have a large empty freezer, don’t fret. You have the heat option. Take a large glass or plastic bowl and place 5 or more pounds of malt in it. Put it in the microwave and heat it to 176 F (80C).Do this for the whole batch. It only takes a couple minutes in the microwave – start with a minute and take its temperature and adjust accordingly. I am not joking. That level of heat kills the eggs. Let it cool and place in air tight containers. But what about the enzymes – won’t they denature? No, there is so little water that the enzymes are barely in contact with moisture. Even in the mash, when the water to grain ratio is low (<1qt/lb) the enzymes take longer to denature at higher temperatures. Do not heat the malt in the oven unless you are toasting it. The malt will take a longer time to heat which could kill the enzymes. There you have it; you can now buy and store grain in bulk and save some coin in the process!

How much yeast is too much?

No one gives a number and neither will I. What I can say is there are standards. The homebrew standard is .75 million cells per milliliter per degree Plato. The specifics are covered in the yeast section. I and some professional brewers like to pitch at the 1 million cells per milliliter per degree Plato area. For a really fast fermentation, some commercial brewers pitch in the 1.5 million . . . area. In fact, this is the standard pitch rate for lagers. That would be 3-4 yeast vials or slap packs in 1.040 wort, and that is still within the recommended range. The upper limit of yeast is when so much is introduced to wort that it barely needs to duplicate in order to consume the oxygen and sugars in the beer. In this case the pitching yeast is doing the fermenting, rather than newly created and highly viable yeast. It will ferment fast but produce more “yeasty” flavors and will not be as usable for future batches. In typical fermentation, yeast will bud 5-6 times. This is a normal healthy cycle. The average numbers of yeast cells in a 5 gallon batch total around five billion. A 10% beer could end up around 32 billion cells total. Overall, it is much easier to under-pitch than over-pitch yeast.

 

Why should I re-hydrate dry yeast before pitching?

Yeast has cell membranes that need to be fluid in order to function. If the dry yeast is simply tossed into wort, then compounds enter the cell membranes that not normally do so. This can hurt the yeast’s viability. When re-hydrated in warm water, the cells can build up their defenses before being bombarded by all the other compounds. It is not required to do this step, but it gets the fermentation off to a good start. See the yeast section for more information.

Why are Belgian syrups easier for yeast to ferment than other sugars?

There are enzymes (invertase) in yeast that convert complex sugars (sucrose) to simpler sugars (glucose and fructose). This process happens before they make alcohol and CO2 because brewer’s yeast cannot turn sucrose directly into alcohol [this is why the Belgian sugar makers say their syrups are more fermentable than complex sugars; however, it is a simple process for the enzymes to convert sucrose to these sugars].

Why should I mashout?

This is not a required step, but it can be beneficial. First of all, most enzyme activity stops (some enzyme activity could theoretically continue until boiling temperatures are reached). This is beneficial because if left at mash temperatures for long period of time it could continue to convert starches and make the beer thinner than was intended. Secondly, sugars are very soluble at higher temperatures. At 170° F the converted sugars will flow very well and you’ll get better efficiency. At the same time, the mash should not get above 170° F. This could cause the grain husks to give off an undesirable astringency. This is less likely to occur as long as the pH stays below 6.0 - sparge water should be acidified. Another way to avoid astringency is to batch sparge. The mash will not get thin enough for the pH to rise above 6.0, provided you keep it to one runoff.

Why doesn’t my iodine starch test work?

Answer 1: you are using the wrong type of iodine. It must be Iodine Tincture. This can be purchased in the same area of the drug store as regular iodine.

Answer 2: you have too much grain/husks in the sample. Try to get just the liquid.

Answer 3: sample is too hot. Get it to room temperature.

Answer 4: use a white plate. Other colors could make the color change hard to see.

Answer 5: You are reading it wrong. The color change happens in the presence of starch. No color change means the mash is done.

 

How fast do enzymes denature in the mash?

Beta β and alpha α amylase (saccharification enzymes) do not denature instantly at a given temperature. Mash thickness must also be considered. Here are the temperatures that result in the denaturing of these enzymes at different thicknesses:

  • Beta amylase denatures completely in 40-60 minutes at 149° F at average mash thickness (1.5 qt/pound).
  • At 149° F and a thin ratio of 2.3qt water/pound malt, beta amylase reduces 90% activity in 10 minutes.
  • At 149° F and a thick mash ratio of 0.9 qt water/pound malt, beta amylase activity reduces 70% after 40 minutes.
  • Alpha amylase denatures in 2 hours at 153 degrees at normal mash thickness.

 

The reason I mention β amylase multiple times is that it is much more sensitive to heat than α

amylase. The higher the temperature and the thinner the mash, the quicker denaturing occurs.

 

How many seeds are in one pound of malt?

 

About 14,000.

 

What is the difference in the Maillard effect (melanoidins) and Caramelization?

Simple answer: Maillard reactions are chemical reactions between sugars and amino acids in high water ratios at boiling temperatures. Caramelization is a non-chemical reaction between only sugars in low water ratios at temperatures above boiling.

Detailed answer: Maillard reaction: 1) an amino acid and a sugar combine with the loss of a water molecule to form an unstable compound; 2) the unstable compound has an isomerization reaction to form ketosamine; 3) Ketosamine transforms to produce one of 3 different products (via one of 3 different pathways): compounds found in true caramelization reactions, large colored compounds (melanoidins), and highly flavored active heterocyclic compounds.

FYI: Sucrose (table sugar) is not a reducing sugar (it is refined and contains no impurities) – it will not form Maillard reactions. Glucose, fructose, and maltose (in other words malt sugars) do react with amino acids to produce Maillard Reactions.

Caramelization is the thermal degradation of sugars which leads to the formation of both volatiles (caramel aromas) and caramel colored products. Caramelization occurs by pyrolysis (thermo chemical degradation in the absence of oxygen) instead of by a chemical reaction in the case of Maillard reactions. Caramelization is catalyzed by an acid or base at temperatures above 220-248F and a pH between 3 and 9.

FYI: Sucrose will caramelize because high heat and low or no moisture causes the sugars to react and darken.