Sav's Sourdough Starters

A couple of blogs that I am subscribed to include Hannah Prescott and Sydney Joyner's blogs, which are titled "Sourpuss Sourdough" and "Let's Get This Bread." This week I have reviewed the research questions they have proposed that they would like to answer with the data we receive from this semester's starters. I also reevaluated my own potential research questions this week to determine what I would like to ask about our data.  Sourpuss Sourdough - Hannah Prescott Hannah asked the following questions:  1. Is there a connection between the type of fruit and the type of microbes found in the starters?  2. Do certain microbes display a particular phenotypic smell in the starters, and does this smell change or become more strong or weak in relative abundance?  3. Did the environment the starters were grown in impact all of the starters as far as which microbes were present?  Summary : I think Hannah has asked some great questions! Hannah's third quest...

During the last two weeks, students have been  submitting  samples of  their sourdough starters  for DNA sequencing.  We will be getting data  and  results back soon, but for now, we will be  practicing  DNA analysis using data from last  semester's  sourdough starters.  What are we sequencing?  The purpose of this research project is to determine the exact sequences of nucleotides within the sourdough starters to figure out which microorganisms are present. We will be sequencing a few very specific genes or regions within a genome of  many different organisms. There are two genes that we will be sequencing for this set of sourdough starter samples; the 16S rRNA gene, which is present in bacteria and the ITS region, which is present in eukaryotic organisms such as fungi.  Shotgun vs Amplicon-based Metagenomic Sequencing We discussed two ways that we could sequence our sourdough starter samples, each having their ...

The Beginning of The End The last update on my starters consisted of observations from February 8th to February 18th.  There was very little progress to share during that time. On February 19th, however, my original control starter began to rise. It was rising pretty consistently for a couple of days, but then it seemed to show less bubbles and growth each day. Its health declined rapidly which led me to dispose of all four starters since I did not have any viable samples to submit for sequencing. Below I have attached images from February 19th and 20th, the days my original control starter showed the most growth.  The two images above are both of my original starters on  February 19th , taken around 9:30 am. At this point, I had been feeding my original starters and newer starters differently. My original starters were being refreshed each day by having 1 TBSP of old mixture taken out and then adding 1 TBSP of water and 4.5 TSP of flour. For the newer starters, I was rem...

Rising Rate Experiment & Graphs Since my starters have not been very reliable or rising regularly, I decided to find a partner to work with to complete the rising rate experiment. I worked with Hannah Prescott on this experiment. She had three starters; a control starter, an apple variable starter, and a strawberry variable starter. She observed these three starters over a period of 2040 minutes. If you would like to see photos of these starters and how the experiment was performed, you can view her blog post about the experiment  here .  Since Hannah actually performed the experiment, I used the data she collected to create the following graphs.  In this first graph, you will see the changes in the absolute starter heights over time. This graph shows exactly how much each starter rose in centimeters throughout this given period of time. Creating and looking at this graph, we were able to visualize and determine that the strawberry variable was more reactive and was r...

 Update on Sourdough Starters On February 8th, 2021, I began a new set of sourdough starters. I made one control starter with just flour and water, and then I made an experimental starter containing flour, water, and an apple slice. Although I used a fresh apple slice instead of applesauce, I wanted to use the same fruit so that my research on cultures would apply to both sets of starters. I have continued to feed my original starters as well. The images below are from the first day I created my new starters.  The image on the left shows the smooth surface of the new control starter just after I mixed the flour and water around 9:00 am. on February 8th. The image on the right is from the same date and time but shows the experimental starter. You can see the chunks of apple in this image. Over the course of a few days, I was able to continue mashing those up better until the experimental starter also exhibited a fairly smooth surface.  OBSERVATIONS On February 10th , the m...

What is DNA Sequencing?  DNA sequencing can be used to determine the order of bases within a DNA molecule. There are four DNA bases which include adenine, thymine, guanine, and cytosine. To understand DNA sequencing, you should know that these bases are the building blocks of DNA molecules and be aware of base pairing. Adenine (A) pairs with thymine (T) and cytosine (C) pairs with guanine (G). If these concepts are new to you, certain phrases such as " A pples in the T ree, C ar in the G arage" may help you memorize which bases pair with each other.  DNA sequencing is extremely important in detecting and treating certain diseases and disorders. This is especially true for cancer patients. DNA sequencing may help their doctor determine the type of cancer they have so that the patient will be able to receive more appropriate treatment. Screening newborns for genetic disorders and other issues has become another important use of DNA sequencing.  I took genetics (GN 311) last...

Experimental Starter: Applesauce While trying to get my sourdough starters to grow, I have wondered if the fruit used in my experimental starter had anything to do with its slow, basically nonexistent, progress. Many of you have probably eaten Mott's applesauce at some point in your life. After doing a bit of research, I found that Granny Smith apples are used in the applesauce I mixed into my experimental starter. I found a really interesting article on the genetic makeup and origins of domesticated apples. I will be using information from that article in this post and providing the link if you would like to check out some of the data yourself! If you would like to learn more about the history and genetics of domesticated apples, more specifically, Granny Smith apples, I suggest you read this post :)  So many apples, so many locations, so many uses!  There are various types of wild apples that have originated in different areas around the world. The apples that we eat today a...