What yeast to use for making ginger beer?
Champagne yeast is what you'll find in most recipes. I've used bread yeast bought in bulk from Costco and been happy with the results. Here's the thing--champagne yeast is meant to attenuate to a super low final gravity and has a super high alcohol tolerance. Ginger beer is, what, .2% abv? Yeast is important in beer making, but in this instance all you are going for is enough CO2 to carbonate your bottle. I'm sure some super taster could detect the difference; but if you want to try making ginger beer at home and you already have bread yeast laying around your freezer, use the damn bread yeast and you really won't notice any difference. I usually do a 1/2 gallon batch and pitch a tea-spoon of bakers yeast into 90F liquid. Bottle, cover with a towel and put it in a warm place (I sit the bottles on top of the griddle space on a 1950's Wedgwood stove that has a rather active pilot light), leave 'em for 12 hours and then put them in the fridge to halt fermentation. Drink within a week, preferably with vodka and lime (i.e. a Moscow Mule) or dark rum (a Dark and Stormy), or enjoy straight up as a soft drink.
Cup of coffee,a 10 gallon aquarium, or a bottle of ginger ale - air pressure?
Assuming that air pressure means "the pressure exerted by the air on the container", then the air pressure is the same in all three cases. The pressure on the interior of the coffee cup is due to the air pressure above the coffee + the pressure due to the weight of the coffee in the cup. The pressure on the interior of the 10-gallon aquarium is due to the air pressure above the water (if there is any) + the pressure due to the the weight of the water in the aquarium. [If there is no water, then there is only air pressure.] If open, then the interior of the bottle of soda experiences air pressure + the pressure due to the weight of the soda in it. If closed, then the interior of the soda bottle experiences the pressure of the carbon dioxide gas that comes out of solution in the closed container. This pressure is not necessarily due to air. === If you meant to ask which container experiences the greatest total pressure on the interior, then it's the 10-gallon aquarium, provided it is filled with water, because water is very dense/heavy. If it is not filled, then your next best bet is the bottle of soda, provided it is closed. If it is open, then it depends on the weight of the soda in the bottle compared to the weight of the coffee in the cup. Otherwise, the air pressure exerted on all three containers is the same.
Have you ever used "active dry yeast" to brew beer? What were the results?
The big risk in dried yeast is contamination by lactic acid bacteria and other spoilage organisms. A spec I just looked at had bugs(lactics, pediococcus and wild yeast) at <3/ml with a pitch rate appropriate for a 6 plato wort, or say <6/ml for a more typical craft brewery 12 plato wort.As a big-brewery brewer my expectation for bugs in the fermenter is nill/100 ml at the start of fermentation. if your yeast source guarantees only <600/100 ml there is a risk there.The risk is that bugs will establish themselves in your brewery at low levels and you will never get them out. Cask/bottle conditioned beers, sterile filtered beers, rough filtered beers will all be at risk of spoilage.You can manage the risk with beer formulation and handling: high hop levels, low pH, high alcohol, short time in distribution, refrigerated distribution etc. Or make sours.You can also manage the risk with yeast handling; only use the yeast once (expensive but safe), early cropping of yeast from fermenters and cold storage ; and possible acid washing of yeast.I’ve had a few beers in the last few months from small breweries that had lactic infections. My guess is that their processes that allowed them to produce a product with acceptable microbial stability for local distribution did not work when sending it 1000 km down the road. I know some of these used dried yeast.A long answer addressing only part of the question. But you need to consider the microbial risk and the product/distribution characteristics when considering a yeast source. Dried yeasts may be highest risk, liquid yeasts usually less so because the production is inherently more hygienic. If you have $500k to spare I’ll help you build an entry-level yeast prop plant that will give you great results if you hire a microbiologist to run it.
Has anyone heard of putting fresh flowers in very hot water in order for them to open fully and last longer?
If roses have wilted because they have been out of water too long or because the stems were not cut underwater soon enough and the stem ends have become clogged, hot water will revive them faster than cold water. The reason is that stems absorb hot water more quickly. Keep in mind that water moves up the stem more rapidly when cut flowers are placed in slightly acidic water. Quite often, you'll see cut roses drooping at their necks (right below the buds). A simple way to revive them is to cut about an inch off the bottom of the stems and place them immediately in very hot water. You should start to see the roses revive after 30 minutes or so. (Flowers that are soft-stemmed wouldn't be able to withstand the hot water and they would probably be damaged) A COUPLE OF HELPFUL HINTS TO PROLONG CUT FLOWERS: Water for cut flowers is best if it is slightly acidic because acid breaks up air bubbles in water by neutralizing the carbon dioxide gas. Air bubbles can clog stems and prevent water from reaching the flowers and foliage. IF you aren't able to use the florist preservatives, you can mix up your own by; A) Mixing any clear citrus-based soft drink (such as 7-Up or Sprite but NOT DIET) with three parts water + 1/2 teaspoon of bleach (to prevent the formation of algae which can plug up stems and keeps them from absorbing water) OR B) Mix 2 tablespoons lemon juice, 1 tablespoon sugar, and l/2 teaspoon household bleach in 1 quart of water. You should change the water in the vase every day and try to cut off the bottom of the stem (at a 45-degree angle) underwater each time. Hope this answered your question! GOOD LUCK with your cut roses and enjoy! - Certified Professional Crop Consultant with a Degree in Plant Science