Author Topic: Calculation of Percentages  (Read 2888 times)

0 Members and 1 Guest are viewing this topic.

Offline scpizza

  • Registered User
  • Posts: 317
  • Demystifying Neapolitan Pizza
Calculation of Percentages
« on: February 02, 2007, 10:49:12 AM »
There are three ways to calculate percentages of ingredients

- as a percentage of flour
- as a percentage of water
- as a percentage of total dough weight

Different people use different ones so we have to convert when communicating.  But I see a much more insidious problem with this situation.

If I say "I increased the hydration of my dough from 60% to 64% and got poor results because if it," that statement could be deeply flawed.  It implies I changed only one variable in my recipe and observed certain results which I can then attribute to just that one variable change.

However my spreadsheet currently calculates salt % as salt/flour.  Thus when I change the amount of water added, the spreadsheet does not change the amount of salt.  But what if the chemically important ratio is not salt/flour, but salt/water?  In that case when I change the amount of water added, I'm really changing the salt/water concentration as well as the water/flour ratio.  I'm really changing two variables.  That's a problem.

To solve this problem, we need to have exactly one scheme of representing percentages for each ingredient and that scheme should be based on _chemical_relevance_ for that particular ingredient.

For example in bacteriological research I've read, scientists speak of salt concentration as generating a certain ionic strength, with flour ignored or seen as a buffer.  Clearly, salt/water concentration is the chemically relevant relationship, not salt/flour.  I submit perhaps salt % should always be represented as salt/water.

Starter concentration in my mind should translate to x number of cells per gram of dough.  Doesn't matter how wet or salty the dough is.  If I have two different 1 gram pieces of dough, and each has the same number of yeast and bacteria cells, they should have the same starter %.  I submit perhaps starter % should always be represented as starter/total dough weight.

For water, I think if you assume the primary chemical interaction is with the flour and we assume a starter hydrated to match the dough hydration, then the time-honored water/flour ratio makes sense.  So we have:

flour
water - as percentage of flour
starter - as percentage of total dough weight
salt - as percentage of water

More accurate, but more complicated too.  Thoughts?
« Last Edit: February 02, 2007, 10:52:33 AM by scpizza »


Offline Bill/SFNM

  • Lifetime Member
  • *
  • Posts: 4042
  • Location: Santa Fe, NM
Re: Calculation of Percentages
« Reply #1 on: February 02, 2007, 11:00:15 AM »
Are you using Jeff's spreadsheet? If you change one ingredient, it maintains the ratio of the other ingredients including salt and water. It also specifies starter amount as a percentage of total dough weight. It has worked well for me and I have modified it for use with all of my favorite bread formulas.

I understand the role of salt in the metabolism of yeast, but the saltiness of the final product is of utmost importance to me. I do not want its ratio to change with the amount of water. If it (and all of the other ingredients) are fixed to the flour amount, then I will always have the desired salt concentration at the end.

Bill/SFNM

Offline Jack

  • Registered User
  • Posts: 404
  • Location: WA
  • Pizza; it's what's for dinner, breakfast........
Re: Calculation of Percentages
« Reply #2 on: February 02, 2007, 11:56:05 AM »
Your spreadsheet needs to tie all the percentages together.  You can do this by insuring the total weight of the dough ball is used in the individual weight component calculations.  It is definitely harder to set up the spreadsheet to do this, all the formulae are more complex, but it will provide true scalability to your spreadsheet.

Each of my weight cells takes the total weight of the dough and divides it by the sum of the total percentages of all of the ingredients, times the percentage of that particular ingredient.  This calculates the weight from the actual percentage of each ingredient, in relation to the entire dough ball.  If I change any one ingredient percent, if affects the total dough percentage and therefore the weight each individual component.  There are a few ways to make the formulae work, but they must all tie in together using the total weight of the dough ball.

Note to Geeks - I guess we should be using mass, instead of weight . . . . . . .  <grin>

Jack
Licensed Enginerd

Online Pete-zza

  • Lifetime Member
  • Global Moderator
  • *
  • Posts: 22314
  • Location: Texas
  • Always learning
Re: Calculation of Percentages
« Reply #3 on: February 02, 2007, 12:01:58 PM »
scpizza,

You make a valid observation but I think it gets a bit more complicated than the salt/water relationship alone. If other ingredients are added to the dough, such as sugar, oil, or vital wheat gluten, or whatever, the same scientific principles apply. I know that you personally may not be concerned about sugar, oil, etc., in the doughs you have been making but some members who are trying to make Neapolitan-style pizzas in their home ovens frequently use sugar and/or oil in their doughs. When Marco first posted a basic Neapolitan dough recipe on the forum, I naturally assumed that all of the ingredients (other than flour) were based on a percentage of the flour. This included the Crescito. Somewhere along the way, I was promptly corrected by Marco and told that the 1-5% Crescito figure was in relation to the water. Even with that, I assumed that the salt, at 45 grams, was in relation to the flour (1650 grams), not water, and have proceeded on that assumption ever since. Otherwise, 45 grams in relation to a liter of water (1000 grams) would be 4.5%--on the surface a seemingly excessive amount of salt. On the basis of the flour (1650 grams), it would be 2.73%, which is a number that is more in line with what most people consider to be a proper number for salt.

Most spreadsheets work along the lines that Bill has discussed, and as Jack has commented. There is a fixed dough weight and if one number is changed, such as percent hydration, the percents of the other numbers do not change. If other percents are changed for other ingredients, the ingredient quantities will change individually but the total dough ball weight will remain the same, principles of chemistry notwithstanding. I have designed a new preferment dough calculating tool with Boy Hits Car (Mike) that works the same way as most spreadsheets. In due course, I expect the tool to be posted on the forum. Because of the many ways that people use their preferments (which includes starters used solely for leavening purposes), we designed the tool so that the preferment can be expressed in any one of the three ways you referenced in your post, including expressing the amount of preferment as a percentage of water. To test the tool, I converted one of Bill's dough formulations to the three different methods, and the results were the same. So as long as the numbers are correct, it doesn't matter how one expresses the preferment. The tool also allows one to include sugar and/or oil, mainly for the benefit of those using standard home ovens. Users also have the option of supplementing their natural (wild yeast) preferments with commercial yeast, as part of the final mix, as is commonly done with many of our members. Yet, the ingredients like salt, yeast, sugar and oil remain fixed from a percentage standpoint.

Peter

Offline Bill/SFNM

  • Lifetime Member
  • *
  • Posts: 4042
  • Location: Santa Fe, NM
Re: Calculation of Percentages
« Reply #4 on: February 02, 2007, 12:21:23 PM »
I had the pleasure of testing the calculation tool that Mike and Peter have been working on. It does a perfect job of properly calculating ratios in a way that is most meaningful to me. These tools are very useful for calculating, adjusting, and scaling ingredient amounts, but are also great for understanding the relationships between the different ingredients.

Bill/SFNM


Offline pizzanapoletana

  • Registered User
  • Posts: 958
  • Location: London -UK
  • Pizza Napoletana as it was made in 1730!
    • Forno Napoletano - Pizza Ovens
Re: Calculation of Percentages
« Reply #5 on: February 03, 2007, 05:43:02 AM »
I may be wrong, but if I remember correctly, from my earliest messages, I mention that ingredients should be measured against water (and this was before even posting the average guideline "recipe" peter has somehow reported :-0).
 
100g more or less flour over a liter of water won't make a perceived difference on the salt level in the dough (it will be spread over 10-11 pizza, less then 10g per pizza ball....

Online Pete-zza

  • Lifetime Member
  • Global Moderator
  • *
  • Posts: 22314
  • Location: Texas
  • Always learning
Re: Calculation of Percentages
« Reply #6 on: February 03, 2007, 06:23:22 AM »
Marco,

Thank you for the clarification. You did indeed talk about salt in relation to water, at
http://www.pizzamaking.com/forum/index.php/topic,1085.msg9700/topicseen.html#msg9700 (Reply 7) and
http://www.pizzamaking.com/forum/index.php/topic,1378.msg13781/topicseen.html#msg13781 (Reply 28).

Peter

Offline pizzanapoletana

  • Registered User
  • Posts: 958
  • Location: London -UK
  • Pizza Napoletana as it was made in 1730!
    • Forno Napoletano - Pizza Ovens
Re: Calculation of Percentages
« Reply #7 on: February 03, 2007, 07:07:10 AM »
Peter,

Thanks for that, but I actually made my point in my THIRD ever message on this forum:
http://www.pizzamaking.com/forum/index.php/topic,861.msg8679.html#msg8679
(5th line from the top)

Ciao

Online Pete-zza

  • Lifetime Member
  • Global Moderator
  • *
  • Posts: 22314
  • Location: Texas
  • Always learning
Re: Calculation of Percentages
« Reply #8 on: February 03, 2007, 07:22:34 AM »
Marco,

Thanks again. I remember that post very well. Since I missed the connection between the Crisceto and the water, it's no surprise that I missed the connection for the salt also. That's one of the reasons I reread all of your posts from time to time. I learn something new every time, although I think I would rather read the stuff from your book on the subject instead.

Peter

Offline scpizza

  • Registered User
  • Posts: 317
  • Demystifying Neapolitan Pizza
Re: Calculation of Percentages
« Reply #9 on: February 03, 2007, 09:09:23 AM »
Hear hear.  Don't tease us any more Marco; write the book.


Offline scpizza

  • Registered User
  • Posts: 317
  • Demystifying Neapolitan Pizza
Re: Calculation of Percentages
« Reply #10 on: February 07, 2007, 11:00:17 AM »
I think the key question is still unanswered.

The question is not should the quantities of each ingredient recalculate when you change one ingredient.  Of course they should, and that's the business of the spreadsheet logic to ensure the total dough weight ends up as desired.

The question is what principles should direct the spreadsheet logic.  For example, should salt % be maintained against flour or against water, etc.  Here is a summary of what I'm hearing so far:


scpizza
Bill
Jack
Pete-zza
pizzanapoletana
water
flour
flour
total
flour
flour
starter
total
total
total
water
water
salt
water
flour
total
flour
water
« Last Edit: February 07, 2007, 11:07:17 AM by scpizza »

Online Pete-zza

  • Lifetime Member
  • Global Moderator
  • *
  • Posts: 22314
  • Location: Texas
  • Always learning
Re: Calculation of Percentages
« Reply #11 on: February 07, 2007, 11:43:14 AM »
scpizza,

Once I understood the distinction, I have tried in my posts on Neapolitan styles using natural starters to express the starter as a percentage of both flour and water. I might express it first with respect to the flour in the dough formulation but indicate in a note or the text what the percent is with respect to water. I have always expressed the salt as a percent of flour.

With only four ingredients, flour, water, salt and starter/yeast, it may not make much of a difference as a practical matter whether the ingredients (other than flour) are expressed as a percentage of flour or water, so long as the numbers are right, although you can probably make a case that the solubility factors dictate expressing everything with respect to water. Not being a chemist, I don't know enough about these facets to state a position one way or another. However, if a dough formulation has a much larger number of ingredients, I don't know if the chemistry supports expressing everything as a percent of water. For example, I am aware of one dough formulation, for the Donatos dough, that includes nine different ingredients, including eggs, dried dairy whey, sugar, oil, and dry milk. I have no idea as to whether it is more appropriate to express all of these ingredients as a percent of water also. As you know, the almost universal practice in the U.S. is to express dough products as baker's percents tied to the flour. I had never heard or read anything about using water as the benchmark until after Marco entered the forum. In fact, although Marco certainly understands baker's percents I don't believe he used them when he posted the original Neapolitan dough recipe. I did the conversions to baker's percents and calculated the thickness factor so that I could scale down the recipe he posted to a few dough balls to try out the recipe.

Peter

Offline abatardi

  • Registered User
  • Posts: 432
  • Age: 53
  • Location: Santa Clara, CA
  • It's MOOPS!
Re: Calculation of Percentages
« Reply #12 on: February 07, 2007, 01:32:16 PM »
Hear hear.  Don't tease us any more Marco; write the book.

I'm sure the book is already written, but it's probably publishing that is the road block... So if anyone has an in with a publishing house speak up.  :-)

- aba
Make me a bicycle CLOWN!


 

pizzapan