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Experiment "Bruxelles2"
Salt Bridges
I failed a three batches of salt bridges before managing to have one stable made.
The right protocol
- Mix 200 ml water, 5 g of agar and 75g of salt in a cooking pan.
- Bring it to a boil while mixing regularly.
- Let it boil for a few minutes (not too much, otherwise you will loose your water)
- Pour the boiling mix in appropriate containers
- Reused glass jars (with an opening having a size close to the widest diameter of the pot)
- Glass petri dishes
- Let them cool down a bit
- Place them in the fridge for a few hours
What not to do
- Use hot water from a kettle and mix everything in a cold pot
- This induces a very uneven mix, where salt and agar are not well dissolved
- Let it sit in the pot beore pouring it on top of the substrate
- Warm liquid may harm the microbes in the substrate
- Most of the agar and salt will sediment at the bottom of the pot, and your mix will not become a gelatin
- Do not forget that the fridge step is important !
- I highly suspect gelatin to be inefficient for this process. My successful batch was made from agar-agar from a chemical provider. I think other sources may be fine, but I have not managed to use them properly yet.