Konvertering SRM<->EBC (var Brew wizard, EBC)

[ken.sentell]

Hej!
Jag har för mig att jag läst någonstans att "Jänkarna" inte är så bra på
att räkna ut °EBC. Jag vill minnas att dom missförstått hur man omvandlar
till °EBC. Jag tror att det stog i något gammalt nummer av Hembryggaren.
Totte.

Det beror nog snarare på att EBC definierades på ett annat sätt förr i
tiden. Det ändrades nån gång i början på 80-talet, för att EBC skulle
stämma bättre med SRM (ungefär samma som Lovibond). Det kan alltså vara bra
att vara skeptisk mot EBC-värden om man inte är säker på att de är uppmätta
med den nya metoden. Numera är omvandlingsformeln EBC = 1.97 SRM.

[snip]

/Fredrik Ståhl

Jag skickade ett brev till Jeffrey Donovan (skapare av Promash) och fick
tillbaka svar om just detta. Här kommer hans svar.

/Ken

Ken, you may also be interested in this question/answer posted on the BBS.
If people are using the "old" method of EBC (prior to 1990), yes, ProMash
would seem light....

Question From User:
-------------------------------

I've encountered a difficulty, and I don't know if it's a bug or the

basic incompatability

between Lovibond, SRM and EBC. When I enter the SRM (Lovibond) color for

darker

grains (using the malt lot analysis) I find that after a certain point

degrees Lovibond

are not consistant with EBC, ie: DWC Aromatic is 19L or 50EBC, however

Promash

will not allow both numbers. Is this a problem with the program or the

systems themselves.

If it's the systems, which scale more accurately predicts final color?

Answer:
-----------
It is neither, I believe it is the fact that the EBC changed the way color
is measured in 1990. Let me give you a quote from Ray Daniels book
"Designer Great Beers', as it describes the situation best:

"....the EBC Technique is a method used to read absorbance in a smaller,
1-centimeter (10-millimeter) cuvette, but at the same wavelength as is used
by the SRM....This technique was adopted relatively recently in Europe;
previously the EBC used a wavelength of 530 nm. The absorbance reasing thus
obtained was the EBC color rating.

The current technique (reading at 430 nm) can be directly compared by the
ASBC method as follows:

SRM x 1.97 = EBC

or

EBC / 1.97 = SRM

.....If you are looking at older values of EBC color, those made prior to
1990 - be catious in making comparisns with SRM color. Due to varying color
measurement techniques in use in the past, the results may not be directly
comparable to current SRM values."

- End of Daniels comment....

Now, ProMash uses the newer conversion model as shown above and applied by
the ASBC (The American Society of Brewing Chemists). The older formulas
(prior to 1990) would have yielded about the result you expected (19L =
49.15 EBC) but is not the current EBC conversion.