Brewing technology · Measurement
The saccharometer
A float that measures how much sugar a brewer has extracted — and, by making waste visible for the first time, quietly rewrote British recipes within a generation.
Before
A brewer bought malt and made beer and had no way of knowing how much of what they had paid for actually ended up in the wort. Malt quality was judged by look, smell and reputation. Whether brown malt yielded as much fermentable extract as pale malt was a matter of opinion, and the prevailing opinion — that darker malt, being more worked, gave more — was wrong. There was no instrument that could settle it.
After
The instrument settled it, and the answer was expensive. Brown malt yields substantially less extract than pale malt, so a porter brewer using it was paying for malt that was not becoming beer. Within a generation London porter was being brewed from a pale base with a small proportion of dark malt for colour and flavour — a different beer arrived at for arithmetical reasons. Gravity also became the language of beer strength, of brewery accounting and eventually of taxation, which is why British beer is described by original gravity to this day.
The historical question this page exists to answer. How the technique itself works is on the brewing process pages linked below.
Why it spread
Fast, and for the plainest possible reason: it showed brewers they were losing money. An instrument that tells a large porter brewery it is wasting a measurable fraction of its malt bill pays for itself immediately, which is precisely the argument the thermometer could not make on its own.
Who is credited
Richardson published *Statical Estimates of the Materials of Brewing* in 1784, which applied the hydrometer to wort and named the result a saccharometer. He did not invent the hydrometer, which is far older; what is his is the application to brewing and the systematic tables that made it usable.
A contemporary record supports this attribution.
What it depended on
These had to happen in this order. That dependency is why brewing technology arrives in chains rather than as isolated inventions.
Adopted c. 1760 – 1800
The saccharometer
Adopted c. 1770 – 1810
Styles that exist because of it
Or that changed materially. A style listed here would be a different beer, or would not be brewable at all, without this.
What people get wrong
The hydrometer was invented for brewing.
Hydrometers long predate their brewing use. What was new was applying one to wort and building the tables that turned a reading into a decision about malt.
Porter changed because tastes changed.
Taste changed too, but the first push was arithmetic. Once brewers could measure extract they could see that brown malt was poor value, and the recipe moved to a pale base with dark malt for colour. Black patent malt in 1817 made that reformulation practical.
Questions
What is a saccharometer?
A hydrometer calibrated for wort. It floats higher in a denser liquid, so the reading tells a brewer how much dissolved sugar the mash has extracted from the malt. John Richardson applied it to brewing in the 1780s and published tables for it, and it is the origin of describing beer by original gravity.
How did the hydrometer change beer?
It made waste visible. Brewers discovered that brown malt yielded far less fermentable extract than pale malt, which had been assumed to be the other way round. British porter was reformulated onto a pale base with a little dark malt for colour, and gravity became the standard language of beer strength, brewery accounting and eventually tax.
Connected
How it works: Mashing · Lautering
Ingredients and packages: Pale ale malt · Brown malt
Dated events: Daniel Wheeler patents black malt
People: Daniel Wheeler · John Richardson
Places: London · Burton-on-Trent
In context: Industrial brewing
Last reviewed 2026-08-29.
Evidence
What BeerHQ knows about this, and how. Every statement carries the state of the evidence behind it rather than being presented flatly as fact.
John Richardson published *Statical Estimates of the Materials of Brewing* in 1784, applying the hydrometer to wort — which he called a saccharometer — and supplying the tables that made a gravity reading usable for comparing malts and costing a recipe.
Backed by a source
Source: Sumner, "John Richardson, saccharometry and the pounds-per-barrel extract" (2001), BJHS 34, 255–273 (BJHS 34, 255–273)
Gravity measurement showed that brown malt yields substantially less fermentable extract than pale malt, contrary to the prevailing assumption, and British porter was reformulated onto a pale base with a small dark-malt addition within a generation.
Backed by a source
Sources: Sumner, "John Richardson, saccharometry and the pounds-per-barrel extract" (2001), BJHS 34, 255–273 (BJHS 34, 255–273); Beer: The Story of the Pint — print