If a recipe calls, among other ingredients, for 1 tablespoon yeast and 5 cups flour and I want to make only half of the recipe are any rules to follow?
Do I just divide the above in half?
I am assuming that you are referring to a bread recipe and if so, you just divide it in half.
Well, you can divide by 2 and get the correct mathematical result, but you are unlikely to get a comparable finished product. You're using bulk measure - that's never consistent. First rule would be: weigh your ingredients: at least the water, sugar, flour. Ingredients like yeast wouldn't necessarily have to be weighed, half of a tablespoon of yeast is 1 1/2 teaspoons; that's close enough for the purposes you describe.
You can scale up or down up to a factor of 4, but don't go beyond that.
I've done that successfully when modifying a formula for use with my 20qt mixer.
Thank you all
Flournwater makes an excellent point about the imprecision in measuring by volume. The chance of large error is very high and you should be working with weight and not volume in order to eliminate that degree of error.
Thank you Jeff for the info
I do work with weight. My post was just an example and that is why I used "cup" as a measure
Why the big thing about working with weight for the home baker? I think that as long as you're consistent in how you measure the results will be comparable. There are many variables with bread baking that can affect the final product even if you do weigh instead of measure - I'm thinking of temp in house, humidity in house, the oven can be "off" for some reason, something could bump/jar the rising bread that could affect it. I'm not trying to be a smart tush; I really do not understand the push for the home baker to weigh.
In this particluar instance it is an issue of scaling the recipe up or down. Measuring by weight is essential for this operation to work.
Beyond that is the issue of how much a cup of flour weighs. There is no answer to that because of the tremendously wide range of variables. A home baker can most definitely wing it and measure by volume but it puts you at an immediate disadvantage with regard to getting the most from any given bread formula.
The difference in measuring by volume vs. weight is a lot greater than you might think. Get your self a little digital scale and I think you will be quite pleased and surprised.
While you will find a large number of experienced bread makers on this forum, it also includes novice bakers and those who want to make a good loaf of bread but have had little or no success in doing so. Once you have enough experience with bread making you certainly can "wing it" with some degree of confidence. But it takes quite a lot of practice to read the dough, understand window pane testing, salt/yeast ratios and the like. Relying on weight rather than bulk measure provides a basis for examining each step of the process and identifying, if necessary, where a particular bread dough formula went "bad" - resulting in a not so good loaf of bread. There are just too many opportunities for error in bulk measure of flour that, where hydration can often be a major factor, it's just better to help people when you can see precisely what the bakers percentages were for the type of bread they are asking for help on.
There are also many different styles for bulk measuring ingredients. Dip/level/pour is popular, sifting the dry ingredients into the measuring cup is another and there's always the "spoon it into the measuring cup" style. Each of those will give you a different result, even among multiple iterations within each style, so bulk references can only be regarded as guidelines, not as reliable units of measure for dry ingredients.
You really can't achieve consistent or accurate results, Jahosacat, unless you scale ingredients. The weight of your cup of flour is going to vary from day to day, and even from flour to flour. It may weigh four ounces one day or six ounces the next. You cannot know for certain unless you weigh it.
I scale for a few reasons. My favorite bread books and recipes don't offer measurements in volume, only in weight. Using a digital scale to weigh the ingredients is more accurate, faster, and leaves little to clean up. Most importantly, I want to achieve the best bread I can possibly bake and that requires accuracy. I can't be accurate scooping flour with a a cup. Finally, there's no option in baker's percentages for volume measurements.
The temp in the house, while a factor, isn't a major one since you can adjust the temperature of your water using a simple formula to calculate the desired dough temperature. Using an oven thermometer eliminates any oven problems, and the only time bumping your fermenting dough will cause it to fall is if it's overproofed.
It all comes down to personal preference and what we hope to accomplish, but judging from some of the postings here by new bread bakers, most problems are caused by using volume measurements.
As you can see there are different points of view on the need to weigh or measure. Your question was more along the lines of scaling up or down and how to handle the items on the ingredient list.
Something that has been missed above is the need for yeast. Yeast is one of those things that seems like it it would be very important to get right but isn't really that important. If a recipe calls for 2-1/4 teaspoons of yeast for 2 loaves and you want to make 4 loaves, you could mix the batch doubling everything EXCEPT the yeast and be fine. The dough will take longer to rise but you will have a better tasting bread. You could also ferment the dough at a temperature a few degrees warmer to speed up the activity of the yeast.
Sure you can divide by half or multiply by 100 but the need for yeast is more a matter of knowing what you want and how long you have to do it.
A good example is Peter Reinhart's Italian Bread with Biga. The biga calls for a tiny amount of yeast the night before to develop the flavors. The next day the biga is happy and full of life and a wonderful aroma. The dough mix has some additional yeast for the balance of the mix but only 1 teaspoon.
I see that there is a lot of important discussion on this subject with some different views.
No doubt the weight measure is the best way to go however as a hobby baker I use both. The scale is in the counter and ready to be used but personally I find that a cup is much faster. So I go along with the recipe; if it is written with cups measure I use my cups and if it is in grams I use my scale.
I also think that keeping notes / photos for each breads it is very important too. I can go back into my notes / photos and compare ingredients or kneading methods etc. and understand what each one does.
Interesting comments on this thread. I have 1500 + bread recipes that I've downloaded over 10+ years and few, if any of them give the ingredients in weights. This site has more people who weigh their ingredients than any other I've read thru the years -and your answers to why have given me much to think about.
I also appreciate the tone of your answers - no lectures!