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Make Your Own Soda (Fermentation 101)

August 8, 2009

There are many reasons to try experimenting in the kitchen. In this case, making your own soda is cheaper, more nutritious, and offers a greater flavor variety than store-bought sodas. Basically, this just water with some bubbles and flavor, and is a lot of fun to make!

The bubbles in store-bought sodas are made by adding carbon dioxide gas to a flavored based under high pressure. The gas dissolves into the liquid – you can get a similar effect at home using one of these seltzer makers. However, I like to use a trick that has been around for thousands of years: yeast. Yeast makes bubbles in beer, and yeast can also make bubbles in your homemade soda.

How does this work? Yeast, like humans, obtain energy from breaking down sugar molecules. This requires oxygen, and is known as aerobic respiration. If there is no oxygen around, humans will die. Yeast however, have a metabolic trick that allows them to survive: in the absence of oxygen, yeast can derive energy from sugar in a process known as anaerobic respiration, or fermentation. The two byproducts of yeast fermentation are ethanol (alcohol) and carbon dioxide (fizzy bubbles). When making soda at home, we will let our mixture ferment for ~24 hours. This is enough time for the yeast to produce a lot of bubbles, but only a tiiiiiny trace of alcohol:


Materials you will need:

2-liter plastic soda bottle
Sugar (or honey, turbinado sugar, agave nectar………)
Flavorings (herbs, fruit, syrups)
Yeast – preferably champagne yeast from a store that carries brewing supplies. Baker’s yeast will do in a pinch.


1. Clean your equipment. For making soda, you don’t need to sterilize everything with bleach (like you would for homebrewing beer or wine), but make sure everything is clean.

2. In a pot, add ~1.75 liters of water, and all of the flavorings you plan to use. Bring the mixture up to a simmer, and let it bubble for 30 seconds. Turn off the heat and let the mixture cool.

3. In a separate bowl, dissolve 1.4 teaspoon of yeast into a small amount of warm water. When the yeast is dissolved, add it to the cooled soda base.

4. Pour the completed soda base into the 2-Liter bottle, and close the cap tightly. Let the bottle sit for 24 to 48 hours. The amount of time is variable, depending on the temperature of your kitchen, etc. At first, the carbon dioxide we be produced as a gas, and will increase the pressure in the bottle. Once enough pressure has been built up, newly produced carbon dioxide will begin to dissolve into the soda base.

You can monitor the fermentation by squeezing the bottle – it should start to feel firm, just like a commercial soda bottle would. Enjoy!


Note 1: When you open the soda bottle, there will be a lot of initial fizz. However, if you pour a glass out, and the soda is pretty flat, don’t worry. All this means is that the yeast needs more time. Put the cap back on, and let it go another day. Play around and have fun – since yeast are alive, some days they will produce more bubbles than other days.

Note 2: If you use fruit puree or other “chunky” ingredients, you can filter the cooled soda base through a cheesecloth if you wish. The resulting soda will be smoother. Just like buying orange juice, you can choose pulp or no pulp.


Recently I made a Blueberry-Ginger-Lemon Sparkler. In a pot I combined:

1.75 L water, 1 cup frozen blueberries (pureed in blender), 1 inch chunk of ginger (grated), 1/4 cup sugar, and 1/2 lemon (whole). I brought the mixture to a simmer – behold the cauldron…..


Then, I added 1/4 tsp champagne yeast which I dissolved first in a little warm water. I added the yeast to the *cooled* soda base (minus the lemon half) and pour into a clean 2 L soda bottle. I went to sleep, and the yeast went to work. The next day, I had:



More fermentation resources:

NOVA’s blog has a post on 45-million year old beer

Matt’s blog Brew and Bake had wonderfully detailed instructions for making your own beer!

Craftzine offers a cool video for making soda using a similar technique.

Cold Drinks, Faster (Heat Conduction 101)

July 28, 2009

The problem: You volunteered bring beer to a picnic, you’re running late, and the beer is warm. What do you do? Whatever you decide, do NOT put them in the refrigerator! It will take well over an hour. There is a simple solution, but first let’s learn a little about heat conduction:

1. Everything has heat
Let’s talk about heat – solids, liquids, and gases are made up of molecules. Molecules vibrate and interact with each other, and this is known as thermal energy. Thermal energy also manifests as heat – a glass of hot water has more thermal energy than a glass of cool water.

2. Heat passes between any two substances 
Heat (or thermal energy) is transmitted between substances, where thermal energy from the warmer object always passes to the cooler object. If you touch a hot iron, thermal energy from the iron passes into your hand, and I have a scar to prove it. Conversely, if you hold a cold soda, thermal energy passes from your hand to the soda. The process of heat (thermal energy) moving from one source to another is called conduction (details, with math here).

3. But, heat does not pass evenly between substances
However, thermal energy does not pass through all substances evenly. Metals, like copper and aluminum conduct thermal energy extremely well. The most important point here is that thermal energy passes through water 30 times faster than through air (geek details here)*! Think about it – the “insulation” in many travel coffee mugs is a trapped layer of air. Heat does not pass through air very well, so this slows down the transmission of heat from your coffee to the outside, keeping it warm and delicious for a long time.
*of course, nothing is this simple. I’m ignoring some other aspects of heat transmission, particularly convection.

4. If you want cold drinks now, do not put them in the refrigerator
So, if you need to chill some beer or wine, by far the fastest way to do this is by submerging your drinks in ice water. This will only take 5-15 minutes!

Heat conduction is neat! Tell me more….
-You can think about this problem in reverse. If you need to thaw something that is frozen, like a piece of chicken, don’t leave it on the counter or in the fridge. Instead, place it in a bowl of warm water – you’ll be amazed at how fast it will thaw.
-When you’re going out in the cold, dress in layers. There will be air pockets between each clothing layer. As you now know, air is a poor conductor of thermal energy, so the layers of clothing will help you retain your body heat better then a single, thicker sweater.
-Otters have thick fur coats that keep air bubbles next to the otters’ skin, which keep the otters warm while they’re diving. Smart move, otters!

Kill Weeds Without Chemicals or Money, Part 2 (Photosynthesis 101)

July 28, 2009

After reading the first part of this lesson, our mission is clear… Kill weeds by preventing their access to sunlight.

This will serve two purposes: By killing weeds that already exists, and by preventing weed seeds from germinating. Even though your garden may look clear, it is full of weed seeds that are waiting to germinate. So, what to do?

Gather your supplies. For this project, everything you need is free. First, get a bunch of old newspaper. Every square inch of exposed soil is going to get covered with newspaper. A thick layer of newspaper, at least 1/8″. So make sure you bring enough! Next, you need mulch. Mulch is applied in a layer all across the garden, and its main purposes are to retain soil moisture and maintain soil temperature. However, when used in conjunction with newspaper, the mulch will actually prevent weed growth. Woodchip mulch is available for free in many cities, including Madison, WI (click here for locations) and San Diego, CA (click here for more info). If you can’t find a municipal source for free mulch, try calling landscaping and wood chipping companies, They usually throw away or recycle their wood chips, so they would be happy to provide you with some for free.

Step 1: Assess the situation. Decide which plants in the garden to keep, and which plants are weeds. At this time, remove any large weeds, but leave smaller weeds that are 1″ in height or less. We’ll just cover those up in the next step. Also, depending on your garden, you may also choose to eliminate some grass, and create a “border” between your lawn and your garden. This will help prevent the spread of weeds from the lawn into the garden. Remember the that soil if full of weed seeds:


2. Next, apply a thick layer of newspaper to cover all of the exposed soil, and any existing weeds and grass that you want to eliminate. I usually take an entire “section” of newspaper, unfold it once, and lay it on the ground. Make sure that the newspaper covers everywhere – right up the the stems of your “good” plants. You can overlap the newspaper sections, and tear them to smaller sizes in order to fit small spaces. Make sure the newspaper covering is thick – about 1/8″.

3. Then , apply a layer of mulch to cover all of the newspaper, The mulch layer should be a couple of inches thick, and should completely cover the newspaper. In addition to preventing weed growth, the mulch layer adds visual interest to your garden.

4. Water the entire garden. This will soak the mulch and newspaper to make sure that they stay in place. In the illustration below, the section on the right is untreated, and the section on the left is covered with paper and mulch as instructed:


After a few weeks, take another look at your garden. I bet the mulch looks great, and that there are hardly any weeds! Without this treatment, you garden would look the the right section of the illustration – the existing seeds would have grown, and the weeds seeds would have germinated, leaving you a lot of work. There may be a few weeds growing through the mulch, but it won’t be difficult to keep them under control:


The reason this works is photosynthesis. Plants need sunlight to grow, and if you cover them up with newspaper and mulch, they will die. No money, no chemicals, and no hassle! Have you ever tried this? Leave a comment and let me know.

Kill Weeds Without Chemicals or Money, Part 1 (Photosynthesis 101)

July 28, 2009

Ah, gardening. Although I love spending time outdoors, I do not enjoy pulling weeds – I would much rather relax with a margarita and enjoy my beautiful plants and flowers. I hate weeds, and with good reason. Weeds grow fast, they grow everywhere, and they spread like wildfire.

Many people use herbicides (chemical weed and plant killer) to do the dirty work of making weeds shrivel up and die. However, these chemicals can be ingested by animals, and will also eventually enter our water supply. Not good. Herbicides also cost money. Wouldn’t it be nice if there was a way to keep your garden weed free that does not involve chemicals or money? Keep reading to learn about photosynthesis, and you’ll learn how to make a better garden.


All living things need to grow, which requires carbon. Carbon is a key component in molecules that are essential for life – proteins, fat, carbohydrates, and nucleic acids (like DNA!). Humans and animals get their carbon from this substance known as food – broccoli, jelly beans, sourdough bread. Our bodies can break down this food and use the carbon to help us grow bigger and stronger.

Plants are a little different. With the exception of Audrey Two and other carnivores (like the venus flytrap), plants are out of luck when it comes to breakfast, lunch, and dinner. But, they can do something much cooler – they literally make food out of thin air. Plants take carbon dioxide gas and turn it into sugar, which they use to grow.

Photosynthesis is the process of converting sunlight and water into sugar and oxygen. You’ve probably heard people taking about “fixing” carbon from the atmosphere. Carbon fixation is simply a fancy term for taking carbon gas from the atmosphere (carbon dioxide) and turning it into organic solids (like sugars). Carbon fixation is important for a number of reasons. As mentioned before, plants rely on carbon fixation in order to grow. Carbon fixation can also help fight global warming. Humans use fossils fuels to power cars and homes, and by doing so we’re dumping tons of carbon dioxide gas into the atmosphere. Carbon dioxide is a greenhouse gas, which is the main cause of global warming. But through carbon fixation, plants are removing some of the extra carbon dioxide from the atmosphere (although not quickly enough).


Image credit: Click

So, when the sun shines on a plant, photosynthesis occurs mainly in the leaves. Here, the carbon dioxide enters the leaf, and it is converted to sugar. In order to deliver this sugar to other parts of the plant, there is a network called phloem (pronounced flow-em) that carries sugar up to the flowers and down to the roots. Photosynthesis also requires water. There is a separate network called xylem that brings water from the roots of the plant up to the leaves for photosynthesis.


So how does this help your weed problem? After reading this, you may have already how to kills weeds without chemicals. All you have to do is keep them away from sunlight. They won’t be able to make food, and they will die. Check back for part 2, and I’ll give you detailed instructions for weed maintenance.

Save Your Soap (Detergents 101)

July 22, 2009

Remember those commercials advertising how you can clean an entire sink of dishes with just a spoonful of soap? Have you ever tried this? It really works. Yes, really.

But it took me a while to figure this out. I have always used waaaaaaay too much soap. I would put a drop into every drinking glass, and on top of every plate. My dishes were sparkling clean. But after some experiments, I found that I can use ten times less soap. My dishes were just as clean, but they were a lot easier to rinse off and I have not purchased Palmolive in a loooong time. Stick with me, and learn why such a little amount is truly needed.

Without soap, how will my dishes get clean? Turns out, there are a lot of thing happening when you do your dishes.

First, plain old water helps to dissolve your crusty food. Often, I’ll fill up a particularly nasty pot with water and let it “soak” overnight. Although I do this mainly because I’m lazy, there is actually a lot of chemistry happening. Water, all by itself, is a solvent – it will dissolve many different types of food. Also, using warm or hot water accelerates this process:


Next, your hands do a lot of the heavy lifting. Whether you use a sponge, a scrubby-thingy, or a cloth, all of that manpower removes stuck on bits of food.

Finally, although water is one of the best solvents out there, there are some things that water cannot handle, namely oil. Since oil and water don’t mix, in order to remove oil from your dishes it takes a special kind of molecule. This is where soap comes in. There are various types of soap and detergents, but their unifying characteristic is that each molecule contains two portions. One portion of the molecule, known as the tail, is hydrophobic. Hydrophobic substances are attracted to oily and greasy things. The “head” of the molecule, however, is composed of many atoms including hydrogen and oxygen (hey, that’s what water is made of!). It makes sense, then, that the head of the molecule is hydrophilic and is attracted to water, and will bond to water and most other food particles.


Soap molecule from here

So as your scrubbing your plates, the little soap molecules will mix with the greasy food molecules, and everything will be easily rinsed off. This is the only role of the soap – as I mentioned above, most of the work is done by the water, and your hands. Therefore, its not necessary to use a lot of the stuff. Seriously, only a little bit is needed. Here’s how you can S.Y.S. (Save Your Soap):

Take any kind of bottle, and put a little bit of dish soap in a bottle, and fill the rest up with water. It saves soap, and it looks pretty too.


You can probably dilute a lot of other household chemicals, as well. Leave me a comment, and share your bright ideas!