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Why use the gold plated filter? – Cores Gold Filter

Why use the gold plated filter?
– Cores Gold Filter

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The purpose of using gold for coffee extraction

It is important for enjoying unique characteristics and flavors of coffee to directly extract coffee oil into the cup, therefore we recommend metal filters over paper filters as oil gets absorbed by paper. t is also known that gold is the best metal for a filter as it is hard to ionize. The chart below shows that gold (Au) is the least likely to oxidize among all metals.
Furthermore, we believe that a little amount of gold ions are making a positive influence on the taste of coffee.
  • Ionization tendency of stainless steel is similar to Copper (Cu). Titanium (Ti) and Aluminum (Al) will become “passive state (*)”therefore hardly produce any metal ions.
    *“passive state”—A state of substance that oxide film is formed as anti-corrosive protection on its surface.
  • Coffee tends to have a more round and better mouth feel when extracted with a gold filter, compared to a titanium filter, although both metals are hard to produce metal ions.
    This shows that small amounts of gold ions are potentially having a positive effect on the taste of coffee (research conducted by Maruyama Coffee).

Unique feature of Cores Gold Filter’s mesh

While the mesh is big enough to be able to see with the naked eye, (therefore unable to remove coffee ground completely) it has the advantage of extracting coffee flavor oil directly into the cup. We recommend light to medium dark freshly roasted coffee, with the grind size of medium to coarse. Since hot water flows freely, it allows fast extraction which brings out fruity and clean characteristics of specialty coffee.
Vertical-shape mesh
Vertical-shape mesh allows hot water to flow smoothly and this shape is suitable for “High temperature-Short extraction” which brings the best flavor and characteristic out of the coffee. Therefore this brewing method is perfect for enjoying fruitiness and clean mouth feel that specialty coffee has to offer.
Cores Gold Filter
with vertical mesh
Vertical-shape mesh allows hot water to flow smoothly without clogging up.
Filter with round mesh
Ground coffee can easily get clogged up in round mesh, slowing down the water flow.
How mesh is made
The etching process is used for making the mesh. This allows hot water to flow freely for fast extraction.
The mesh is designed to encourage smooth flow of hot water.
Cross section of the mesh
  • Due to the nature of metal filters, there will be a small amount of ground coffee in the cup, however, this does not affect the quality of the cup. You may choose not to drink entirely and leave the coffee grounds on the bottom of the cup.
  • We recommend using freshly roasted coffee, in order to hold hot water long enough.
Read more”Types of hand brewing methods”
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Types of hand brewing methods

The same coffee can taste differently depending on brewing methods. There are various types of hand brewing methods, so you can change brewing methods and coffees depending on your tastes or feelings.

Gold Filter

Paper Dripper

Nylon

Flannel Filter

French Press

Aero Press
  • Recommended grind size: Medium – Coarse
  • Extracts adequate amount of coffee oil
  • Brings out the full characteristic of coffee
  • Easy to brew with less mess
Cores gold filter
These gold plated mesh filters last for years, saving money on continued purchasing of paper filters, and it is easy to clean. Gold is highly resistant to chemical reactions, therefore the gold filter prevents coffee from becoming oxidized and brings the best flavor out.
Although coffee grounds will not be completely filtered out, (unlike paper filtered coffee) this filter is capable of extracting the coffee oil, which is the essence of coffee flavor, directly into the cup.
Since this filter brings out the full characteristic of coffee, it is best suited for brewing light to medium dark specialty coffee, with grind size between medium and medium coarse.
Extraction time will be short due to the free flow of hot water. This is suitable for bringing out clean and fruity flavors that specialty coffee offers.

  • Recommended grind size: Fine – Coarse
  • Bright and clean mouth feel
  • Relatively affordable
  • Easy to maintain
Paper Dripper
Brewing coffee with the paper filter is easy therefore quite popular in Japan.
Since coffee grounds are not going through the filter, this brewing method makes coffee clean and smooth in the cup. On the other hand, coffee oil, which is an important source of coffee flavor, is blocked by the filter and doesn’t come out.
A dripper could be conical or flat-bottomed depending on the manufacturer. The lengths and positioning of ribs, as well as the number of holes can also vary.
These differences will alter the flavor profile of the extracted coffee. For example, long ribs will encourage faster extraction since there is less time for hot water to contact with coffee, it makes a clean and light-bodied cup. On the other hand, shorter ribs will slow the extraction therefore, ground coffee will contact with hot water longer, to make coffee richer and full-bodied.

  • Recommended grind size: Medium – Medium coarse
  • Extracts adequate amount of coffee oil
  • Easy to brew with less mess
  • Costs less than metal filters
Nylon Filter
Comparing to paper filters, nylon filters are more economic as they are washable and reusable.
Mesh is generally bigger than paper filters and there is a variety of mesh sizes available. While paper filters absorb coffee oil, which is an important source of coffee flavor, nylon filters allow coffee oil to be extracted into the cup, just like gold filters.
However, an uneven pattern of mesh makes flavor inconsistent and the smell of nylon could sometimes be carried into the cup as well.

  • Recommended grind size: Medium – Coarse
  • Round and thick mouth feel
  • Highlights sweetness and takes off some sharpness
  • Enables to give variety to tastes by brewing techniques
Flannel Filter
This brewing method is said to extract round body and full aroma out of a coffee.
Unlike paper and metal filters, the cloth expands when hot water is poured over it. This will help extract various flavors of coffee with round and full-bodied characteristics.
However, you need to have the special skill of slowly pouring hot water, drip by drip, in order to brew properly. In addition, the cloth filter is required to be washed each time, making this brewing method unpopular for domestic use.

  • Recommended grind size: Medium – Coarse
  • Abundant oil extracted for rich aroma and mouth feel.
  • Easy to use and consistent flavor
  • Looks good as an object on the table
French Press
Ground coffee is soaked in hot water before the metal filter is plunged down and coffee is poured through.
Mesh is usually made from metal or nylon which enables coffee oil to be extracted into the cup. Since coffee is infused in hot water for 3-4 minutes, every component including the ones with unpleasant characteristics will be extracted. Although this could be both advantageous and disadvantageous, this brewing method is suitable for high quality specialty coffee.

  • Recommended grind size: Medium
  • Suitable for brewing small amounts of coffee quickly
  • No coffee grounds, clean taste
Aero Press
Aeropress uses air pressure, which is applied manually, to extract coffee. Although there are aftermarket metal filters available, it usually makes use of paper filters therefore, coffee oil is not extracted. It makes cleaner coffee than French Press because it extracts all components of the coffee with the exception of coffee oil.

Gold Filter

  • Recommended grind size: Medium – Coarse
  • Extracts adequate amount of coffee oil
  • Brings out the full characteristic of coffee
  • Easy to brew with less mess
Gold Filter Cores gold filter
These gold plated mesh filters last for years, saving money on continued purchasing of paper filters, and it is easy to clean. Gold is highly resistant to chemical reactions, therefore the gold filter prevents coffee from becoming oxidized and brings the best flavor out.
Although coffee grounds will not be completely filtered out, (unlike paper filtered coffee) this filter is capable of extracting the coffee oil, which is the essence of coffee flavor, directly into the cup.
Since this filter brings out the full characteristic of coffee, it is best suited for brewing light to medium dark specialty coffee, with grind size between medium and medium coarse.
Extraction time will be short due to the free flow of hot water. This is suitable for bringing out clean and fruity flavors that specialty coffee offers.

Paper Dripper

  • Recommended grind size: Fine – Coarse
  • Bright and clean mouth feel
  • Relatively affordable
  • Easy to maintain
Paper Dripper Paper dripper
Brewing coffee with the paper filter is easy therefore quite popular in Japan.
Since coffee grounds are not going through the filter, this brewing method makes coffee clean and smooth in the cup. On the other hand, coffee oil, which is an important source of coffee flavor, is blocked by the filter and doesn’t come out.
A dripper could be conical or flat-bottomed depending on the manufacturer. The lengths and positioning of ribs, as well as the number of holes can also vary. These differences will alter the flavor profile of the extracted coffee. For example, long ribs will encourage faster extraction since there is less time for hot water to contact with coffee, it makes a clean and light-bodied cup. On the other hand, shorter ribs will slow the extraction therefore, ground coffee will contact with hot water longer, to make coffee richer and full-bodied.

Nylon

  • Recommended grind size: Medium – Medium coarse
  • Extracts adequate amount of coffee oil
  • Easy to brew with less mess
  • Costs less than metal filters
Nylon Filter Nylon filter
Comparing to paper filters, nylon filters are more economic as they are washable and reusable.
Mesh is generally bigger than paper filters and there is a variety of mesh sizes available. While paper filters absorb coffee oil, which is an important source of coffee flavor, nylon filters allow coffee oil to be extracted into the cup, just like gold filters.
However, an uneven pattern of mesh makes flavor inconsistent and the smell of nylon could sometimes be carried into the cup as well.

Flannel Filter

  • Recommended grind size: Medium – Coarse
  • Round and thick mouth feel
  • Highlights sweetness and takes off some sharpness
  • Enables to give variety to tastes by brewing techniques
Flannel Filter Flannel (cloth) filter
This brewing method is said to extract round body and full aroma out of a coffee.
Unlike paper and metal filters, the cloth expands when hot water is poured over it. This will help extract various flavors of coffee with round and full-bodied characteristics. However, you need to have the special skill of slowly pouring hot water, drip by drip, in order to brew properly. In addition, the cloth filter is required to be washed each time, making this brewing method unpopular for domestic use.

French Press

  • Recommended grind size: Medium – Coarse
  • Abundant oil extracted for rich aroma and mouth feel.
  • Easy to use and consistent flavor
  • Looks good as an object on the table
French Press French press
Ground coffee is soaked in hot water before the metal filter is plunged down and coffee is poured through.
Mesh is usually made from metal or nylon which enables coffee oil to be extracted into the cup. Since coffee is infused in hot water for 3-4 minutes, every component including the ones with unpleasant characteristics will be extracted. Although this could be both advantageous and disadvantageous, this brewing method is suitable for high quality specialty coffee.

Aero Press

  • Recommended grind size: Medium
  • Suitable for brewing small amounts of coffee quickly
  • No coffee grounds, clean taste
Aero Press エアロプレス
Aeropress uses air pressure, which is applied manually, to extract coffee. Although there are aftermarket metal filters available, it usually makes use of paper filters therefore, coffee oil is not extracted. It makes cleaner coffee than French Press because it extracts all components of the coffee with the exception of coffee oil.

Updated in February 2016