I run a relatively large cottage bakery. To convey our scale, we process about 600lbs or 275kg of flour weekly. I've ready through some of the other posts related to this topic made over the years, but am looking for a bit more insight into the use of sourdough starter as a composting material.
My goal is to start farming on my property as well. I want to produce my own compost, for the sake of enriching our soil here in Arizona. We try to keep our starter management pretty strict, but there are days where we have extra starter leftover. On average, through the week we might have about 20 kg of starter that is leftover. Additionally, we have a fair amount of scrap dough from croissant production that we compost. While we produce products from the scrap cuttings from the 3rd tri-fold and final roll out, we have been discarding cuttings from the first and second tri fold.
I read in a thread on this forum dated from 2010 that starter, being basically pure starch, functions as carbon in the compost heap. I was hoping to verify this with other opinions? Also, would scrap dough, specifically enriched scrap dough also be primarily a brown material, or carbon? Currently, I am studying, An Agricultural Testamament, by Sir Albert Howard, thought of as a sort of Bible to the original organic movement. In it, he describes his composting process as adding about 6 inches of green material (e.g kitchen and bakery food waste), and then topping this with 2 inches of animal processed brown material, in other words urine soaked animal bedding such as wood shavings. We keep chickens, and are considering a couple miniature dairy goats, so I plan on using the bedding from that source.
My current plan would be to discard all household compostables into 50 gallon drums including any spent starter, and then charge my compost pile with a combination of this and animal bedding, topping with a layer of soil. I would create 5 foot heaps, and then actively manage them. For the past year we have been feeding compost bins with our compostables and having them hauled away by a service. Our household and bakery produce roughly 50 gallons of compostables each week, or 1 barrel.
Questions summarized:
1. Is starter a brown material in a compost pile?
2. Is scrap dough a brown material in a compost pile?
3. If both starter and scrap dough are carbon, should I keep a separate barrel for these from my other kitchen waste?
Disclaimer: I am a biologist but no compost expert. I've passively "maintained" compost piles for the past few decades, but use and value them more as destinations for kitchen waste and only lazily thereafter as sources for garden soil enrichment.
That said, I would assign baking detritus to the "brown" category. I tend to classify compost input based on relative carbon versus nitrogen abundance (C:N ratio). Baking waste is of course very C-rich. However, with enough dairy in it (read: croissants), it moves closer to N, thus more green. This is probably a good example of how the brown versus green dichotomy is an oversimplification. It's a continuum with brown and green at opposite ends.
Coming up with enough green (N) to balance your exceptional C load will be a challenge, especially in AZ where you're probably not mowing lawns or cutting alfalfa. Maybe hook up with a lawn care company to take some of their collected cuttings off their hands, assuming enough people do maintain lawns there. Or maybe a riding stable that needs to off-load some manure.
If there ever was a question posted to TFL that was arguably relevant but from deep left field, yours has to be it. And thanks for the Sir Albert Howard reference. Geez, I haven't thought about that (and Forty Acres and Independence) for 40 years. Brings back memories of expired/retired dreams.
Good luck!
Tom
I can see a couple of other issues that need to be considered.
First, in addition to carbon and nitrogen, the other two essential "ingredients" for composting are proper management of oxygen and water. Bread dough is a rather wet, heavy ingredient for compost. Unless it's adequately mixed with sufficient bulky dry ingredients it could easily become anaerobic (a smelly mess). A proper balance of the four ingredients is the primary objective of the "manager" of a compost pile.
Second, it is usually strongly recommended that animal products (butter, bones, meat, cheese etc) NOT be incorporated into a compost pile, primarily because they attract pests. All that butter is certain to attract whatever rodents, raccoons, etc that you have in Arizona. Fat also can impair the composting action and might even persist into the final product.
You would need to incorporate a lot of oxygen, a lot of nitrogen and a lot of dry material to fuel a compost pile containing butter-laden bread dough. You'll probably also need a pest-proof container too.